How can I create different roles but shared the same pages in php?

I'm currently search for a code and I'm doing a view data page where the view page can be see by admin and staff. Unfortunately, when the admin login and use the system, the admin wants to see the view data. after view data, admin click the "go back" button in the view page. So, it supposedly go to the admin main menu but mine, it goes to staff main menu. To solve this, do I need to use IF ELSE for the "go back" button? or I need to use the SESSION for admin pages and staff pages? For the session, I only found code for login session only. I hope someone can help me.