# Create Simple Rule Flow
## How to create a simple decision tree
Let's advance one step at a time.
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In this tutorial, you need to have knowledge of [Decision Tables](https://academy.decisionrules.io/rule-types/decision-tables) or [Scripting Rules](https://academy.decisionrules.io/rule-types/scripting-rules).
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### 1. Create Decision Tables
We have already learned how to create rules in previous tutorials, so let's skip it now and import these decision tables:
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Clients
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* **Clients -** a rule that determines the maximum loan according to the client's age and salary
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* **Loan Type -** a rule that determines the maximum loan tax according to how much and for what the client wants to borrow
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* **Bank Solver -** a rule that calculates how much the client pays in total
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How to import [Rule](https://academy.decisionrules.io/rules/export-and-import-of-the-rules/import-rule)
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### 2. Go to Create rule
To display the rule creation pop-up click the **Create Rule** button on the sidebar.
### 3. Create a new Rule Flow
You will be prompted to provide a name and choose between **SAMPLE RULE** or **EMPTY RULE**. The new rule will be created and its detail will be displayed. We will continue in the Rule Settings tab.
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In our case, we recommend you select the empty rule.
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### 4. Set Rule Flow settings
When you click on RULE SETTINGS on the top left corner, the scripting rule's detail will appear first to set some information. We will change the name of our script. To do this, click on it's name, enter one you like and press Enter.
Since we do not want this rule to be available yet, we will change its status to **"Pending"**. To do this, click on the current status **"Published"** and then select **"Pending"**.
To apply these changes, we have to click on the **Save** button at the bottom of the page.
### 5. Create an Input and Output model
We will now create an input and output model, which will then be used to set conditions and results. You must be in **Rule Flow Settings.** There are 2 ways to create these models:
* **Simple editor:** It is intended for inexperienced users who do not know the syntax of JSON files.
* **JSON editor:** It is intended for an experienced user, with JSON knowledge.
#### Create with a simple editor
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After creating an input or output model, we must always confirm the changes with
the **Save** button
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#### **Input model**
First, we delete all created objects by clicking on the icon (in case you chose Sample Rule Flow). Then we will add our specified requirements (**age, salary, loan, loanType**). In our case, we create a root for each request by clicking on the button.
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If our model were more complex, we would add descendants. More information is described [here](https://docs.decisionrules.io/doc/decision-tables/input-and-output/simple-editor).
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#### **Input model Example:**
#### **Output model**
We set the output model similarly, where we set as root **loan**, **tax**, **totalPay** and **message**.
**Output model Example:**
### Create using JSON editor
#### **Input model**
First, we will create one object into which we will put other objects with our requirements. We will create one empty object for each request.
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Our model is simple, these objects do not contain any others (embedded attributes). For more complex models, more information is [here](https://docs.decisionrules.io/doc/decision-tables/input-and-output/json-editor).
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#### **Input model Example:**
```javascript
{
"age": {},
"salary": {},
"loanType": {},
"loan": {}
}
```
#### **Output model**
We set the output model similarly, where we set as root **loan**, **tax**, **totalPay** and **message**.
**Output model Example:**
```javascript
{
"loan": {},
"tax": {},
"totalPay": {},
"message": {}
}
```
### 6. Creating Rule Flow schema
1. To create Rule Flow schema go to the Rule Flow Designer tab. At the start the canvas is empty. Add there input, output, and three empty rules with buttons in the top-right corner: **Add Input** , **Add Output** , **Add Rule** .
2. Click on the Empty rule to display the sidebar. By button **Select Rule** choose a rule, that will be in place of the empty rule.
3. Connect rules together and to input box and output box. In this case, the correct connect is as follows:
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The rule should look as in the picture above.
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### 7. Map data
To know, which data has to go where we have to map the data.
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If the rule has no inputs mapped. It borders in orange and displays a warning icon
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The example Rule Flow - **Clients** and **Loan type** works with user input data and subsequently, **Bank solver** works with input of user data and with outputs from previous rules makes the decision and sends final outputs to the output box.
#### 7.1 Data mapping Clients
Open data mapping by clicking on **Data Mapping** .
**Global variable** means where the rule takes data from and **output** means what data. Because this rule is connected immediately after the input box, only **user input data** can enter it.
Correct mapping of **Clients** from example:
#### 7.2 Data mapping Loan type
The loan type is also directly connected after the input box, so only **input user data** will also enter it.
Correct mapping of Loan type from example:
#### 7.3 Data mapping Bank solver
The **bank solver** is the final rule, that takes data from both the **previous rules** and the **input box.**
Correct mapping of Bank solver from example:
#### 7.4 Data mapping Output box
The final output can be data from any rule, so it is necessary to map the Output as well. In this example we want the following data to be in the output:
* **Loan** - the amount the customer wants to borrow
* **Tax** - tax of the loan
* **TotalPay** - the amount the customer pays
* **Message** - that confirming the loan or explaining its refusal
Correct mapping for output:
### 8. Test of created Rule Flow
Now we can test our Rule Flow in Test Bench. Before testing the rule, we must change the status of the decision table to **"Published"** or have to **debug mode ON**. Debug mode allows you to test Rule Flow even when it is pending and at the same time writes data information to the debug mode console.
Now you can test your Rule Flow as you like, but for a positive result, it is necessary to have loanType set on **"household", "car"** or **"vacation"** because our bank does not lend to anything else.
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You can add new loanType variables in the Loan Type rule via [Preset values](https://docs.decisionrules.io/doc/decision-tables/table-operations/valid-values).
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You can find more information about input and result at [Solver API](https://docs.decisionrules.io/doc/api/rule-solver-api).
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#### Request body example:
```javascript
{
"age": 30,
"salary": 4000,
"loanType": "household",
"loan": 30000
}
```
#### Response body example:
```javascript
[
{
"loan": 30000,
"tax": 1.15,
"totalPay": 34500,
"message": "eligible for the loan"
}
]
```
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More information about Test Bench is [here](https://docs.decisionrules.io/doc/other/test-bench).
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