Dropdown menu populated from API call on a form?

Dropdown menu populated from API call on a form?

Hello,

I am new to Zoho Creator.  I want to understand how I can create a form with a drop down menu that pulls data from an external API.   

I tried creating the drop down menu first and then looking at the options to see if there is a way to populate it, but I could not find a way to do this.

I also created a standalone function using the deluge scripting language to make the API call, but I am not clear on how to connect it to my drop down menu on the form

How can I do this?