editing single or all selected users in a table with checkboxes - AngularJS

I'm loading a json into a table. I want my 'edit' button to edit a single row and my 'edit selected' to edit only those rows which are checked, but I can't figure it out. I only managed to get it to edit all rows at once.

example.json: https://pastebin.com/d8zDrxe5

index.htm: https://pastebin.com/acKyM0aG