# Setting up Chap Modeling App in DHIS2

This document describes how to install the Modeling App in your DHIS2 instance. 

**Requirements:**
  - DHIS2 version **2.39+**

## 1 Setting up Chap-Core REST API

1. The Modeling App requires communication with an instance of the CHAP-Core REST-API. For using the Modeling App in a production environment, it's recommended that the CHAP REST-API has been [set up on a permanent server by a system admin](running-chap-on-server). 

    > 🛈 Alternatively, you can follow [the instructions on how to setup a CHAP REST-API locally using Docker](../installation/docker-compose-doc.md). 

2. Verify that you have access to the CHAP REST-API and that it's running correctly, by visiting `<your-url-to-chap-server>/docs`. A Swagger page (REST-API documentation) should display. 

    > &#x1F6C8; If you're running the REST-API as a local Docker container, verify by going to `http://localhost:8000/docs`.

## 2 Install Modeling App

The modeling app is available in the DHIS2 app hub and can be installed from there.

## 3 Configure CHAP Core URL

Finally, the Modeling App needs to know which URL to use to communicate with the CHAP Core REST-API. By clicking "Edit CHAP Core URL" located at the right-side menu, a modal should display where you can configure this setting.

Set this value to `<your-url-to-chap-server>`. 

> &#x1F6C8; If you're running the REST-API as a local Docker container, this value should be set to `http://localhost:8000`. 

<img src="../_static/edit-chap-url.png" alt="drawing" width="400"/>

After clicking "Save", the Modeling App should reload and start to fetch and send data to the provided URL.