Set a Custom State Date Based on Form Month and Year value

I have a form with the month and year, each a drop down. I need to be able to set a custom state of csDate on the page based on the selections from the drop down. The drop downs are both text. The months in the month drop down are January, February,…

The date set for the custom state date can be based on the 15th of the month.

So for example, if the user selects the month January, and the year 2025, I need the my custom state’s date value set to January 15th, 2025.

Any suggestions of how to accomplish this?