Making a page accessible only to users with a certain level

Good morning, I have a login system with php and mysql, in the database I have 2 users, one has Admin level (0) and the other Master (1), I have the login page that asks Username and The person's password and checks if the inserted data hits the DB, after logging in correctly, the page redirects the user to a page of the system admins, on this page there is a side menu where it has several buttons, each one redirecting to a page such as the Post and Changes page. Here is my problem: the users page, this page should only be accessed by users whose level is Master (or 1), but I do not know how I would do this, I tried using sessions and query, but always ends up giving in error or letting go any user rather than bar those who are Admin (or 0).