Using a script to generate docs from rows in Google Sheet if checkbox is checked

I'm trying to generate Google Docs / PDFs from rows in a Google Sheet. My aim is for the user presses a UI menu button, and it will only generate the Docs if a checkbox is ticked for that row.

I've got the rest of the code working, its just finding the why to get the script to check if a checkbox is ticket and only generate the doc if it is checked.