i wanted to add a new tab with new functionality. I would like to have a page like the users page where I can create all the contacts and then add them to a Case using a select list. I figured out how to add a new tab, but although I just copied the users.php to another name and added that to the tabs in the cm_groups table, it just shows a blank page.
Can you point me in the right direction to get started? I have a development background in SQL Server, dotNet, have been learning php, Vue.js, React.js, node.js, MVC with various languages.