How to setup site to check if user is admin to grant access to admin panel?

[NoizeDev]

I apologize in advance if the title in unclear. I am fairly new to PHP/MySQL programming.

I have a script I am working on - I have the login, register setup correctly and working fine. I have the pages restricted so that you're required to login. I am now trying to work on an administration panel, my users table in the database is currently setup as follows;

id
username
password
created_at

I want to add another column called is_admin and the default value set to 0, where if is_admin is set to 1 then user is admin. I know how to set that up in the database, but I am stuck on the part where I want the admin page to check if user is admin by checking if the is_admin = 1 then the user can view the admin panel - where if the admin is set to 0 then is redirected to the home page...

I am sorry if this is confusing - still learning!