The Checkout UI Custom app is responsible for customizing your store's Checkout UI through the admin's interface.

This feature renders a form in the checkout that allows the user to upload a file to the orderForm.

1. Using your terminal and the VTEX IO CLI, log into the desired VTEX account.
2. Run vtex install vtex install vtexarg.file-manager-rest on the account you're working on.
3. Run vtex install vtex.checkout-ui-custom@0.5.3-hkignore.1 on the account you're working on.
4. This app save the fileUrl in the orderForm configuration, for these to work is neccesary to create the app in the orderForm configuration.

1. First of all, you should get your current orderForm configuration.
2. Through Postman, make a GET request to this endpoint https://{{account}}.myvtex.com/api/checkout/pvt/configuration/orderForm.

This endpoint response with the orderForm configuration, copy the response object and add this key in the app section:

3. POST the new orderForm configuration with the new app.
4. Through Postman, make a POST request to this endpoint https://{{account}}.myvtex.com/api/checkout/pvt/configuration/orderForm.

It's important to make the GET request before the POST so as not to overwrite any pre-existing orderForm configuration.