Updating a record from a list view using the action dropdown

I'm still on the learning curve as a SugarCRM developer. I've done significant amounts of development on the back end (logic hooks, database work, scheduled jobs) but am still learning the ropes on the front end. I could really use some help understanding how to make this happen.

We have a custom module that includes a status dropdown. A set of our users spend much of their day in the list view of this module. One of their key actions is to update this status field. I've been asked to enable updating this status directly from the list view, which would simplify their workflow a lot.

I modified the modules recordlist.php file to add the status options in the dropdown (see the attached image). So if they select "Mark Complete", the status field should be updated to "Complete." The column in the listview should update to refresh the new value as well.

How do I make it so Sugar is "listening" for this action and makes the appropriate update?

Does the update of the record itself happen in Javascript on the front end? Or does the action trigger a process/call on the backend, with PHP code ultimately updating the field and saving it?

Thanks for any help you can provide.