Open CSS modal from PHP generated table row

I open a modal by clicking on a button that's in a table. There's one of these buttons in each row. The modal is intended to provide a way of editing the data for the user in the row containing the button that was clicked. The modal opens, but how do I:

1. initiate the JS for the modal's edit process
2. pass the id from the row to JS
3. set the focus on the first input text box
4. I plan to use JS to confirm the delete request as well

I'm fine to use AJAX for updating tables. I've nearly got all the mechanics of the application working without using JQuery, Bootstrap or any other libraries and would like to keep it that way. This is likely the only Web app that I'll ever write and requiring more work is acceptable. I read that the <dialog> element isn't supported by Edge or IE, so that's not an option. Thank you for any assistance that you can provide.
sampleModal.php