Incompatible type when setting a list

Hey! I am new to Bubble and I feel a bit stuck…

I am making a Form with a Multi dropdown (plugin) which in populated with data from Airtable. This part works fine.

Next , I am trying to send the selected dropdown data to Airtable. Unfortunately, when I try to “set list”, the Dropdown data has an “incompatible type”.

Any ideas how to get the selected dropdown data and turn it into a list? (Airtable requires list of IDs, even it’s just one ID of the selected item)

Perhaps set list isn’t the right expression. Maybe category isn’t a list, just a choice.

JobCategory is just a Multi dropdown element. The actual type is a Filter (that is populated from Airtable to the dropdown).

And then I am trying to add a State to this Multi dropdown when the value is changed. I create a State called SelectedCategoriesIDs. And I add a list of IDs to this state.