Steam Login

Please know a little about how [login to view URL] Works. Hello this website needs to use Steam login [login to view URL] The Idea of this is Basic. A easy design that has a area for the User to click the Steam Login. Once the user logins it logs the Steam ID into mysql database mybb_user where the forum account is already made its just updating stuff in the MYSQL. So lets say John doe is his username on our website. He wants to add his steam account into his user profile on our website. He would go to the website you are making for me Click the login button and once he logins from steamAPI It sends his steam ID: to our MYSQL mybb_user where his profile is stored on our database. If that user already has a STEAM ID their I do not want it where users can update or change it without it being deleted by an admin first. So lets say they alrady have a STEAM ID: in the user profile of that person. It will not let them update that profile without having an ADMIN delete it from the user profile so they can not change it without anyone knowing.