Zoho CRM: assign task to user in user field

Zoho CRM: assign task to user in user field

Hi,

I would like to assign a task to a user in my Deal module which is not the Deal owner, but rather a user assigned to a custom "User field".

What would be the function to:
1- Fetch the user ID
2- Create task and assign to user
3- Relate task to Deal

The API name of my user field is: "User1"

Thank you!