Add values from an input tag

I have an issue where I have (up to) 5 checkboxes named Author and depending on if they select that checkbox is makes a value from the name Author like so “1,3,5” Obviously depend on the box you select. Now I am wondering two things how can I make a script that does a command depending on what number is in the named value and have it process 5 different named values? I have tried strcmp but I don’t think I grasp the concept as a whole yet.

Also in #PHP _↴