Create the Flow
The flows can be created in many ways to involve approvals, or other steps needed based on business requirements but to keep things simple we will skip the pre-checks and build a direct flow that after a user submits we can invoke the REST call and add the user.
Get Catalog Variables from Catalog Item (The user input form)
This step is essential since this is where we capture the user’s input. So add the action, drag in the RITM Record object and select the variables for the flow to use.

Add the REST Action
Since we created the action with the inputs once you drag the Rest action you will have the field inputs to fill in, they could be static but since we are letting users pick from choices we can simply add the variable to the field and the request will go with the selection.
