You’ll likely have to work that into your theme, unless it’s just pure PHP functionality with no views, in which case you’ll still have to work it into your theme but it’ll be much less of a hassle.
Look up theme development for WordPress.
If you need views, look up the Theme Hierarchy for some good pointers.
If not, look up the functionality of the functions.php in all themes, and how it works.
You’ll likely have to work that into your theme, unless it’s just pure PHP functionality with no views, in which case you’ll still have to work it into your theme but it’ll be much less of a hassle.
Look up theme development for WordPress.
If you need views, look up the Theme Hierarchy for some good pointers.
If not, look up the functionality of the functions.php in all themes, and how it works.
Can you be clearer on what you are trying to do.