PHP, SQL, HTML Website Project Assistance

I am developing a website with some team members and I have created a PHP file (Edit User Information) that extracts the appropriate information that is currently in our "Customers" table in our database. This works but I am currently manually entering an user ID to identify the user in the database in the code, just to test the code to make sure it works properly. Once the user clicks submit after entering any new information, it is then passed to another PHP page that I created (Update User Profile) that updates our database with the new information and simply displays a comment that says "Updated Successfully". All I need help with is: (1) writing code that passes session variables between my team member's User Login page & Create Account page, to my User Profile page. (2) Writing code that directs the user back to the User Profile display page after the Update User Profile page is executed. (3) Writing code that displays the new/updated information on my User Profile display page. My main issue is syntax. I have all of the PHP code that initiates and accesses our database but I am a computer programming novice and need help with writing the appropriate code in the appropriate lines :) I am looking to connect with an expert that will be able to help me complete my portion of the project by Sunday night, May 9, 2021!