I’m trying to move my Instagram app back to my Home Screen and can’t figure out how

Swipe all the way to the right until you reach the App Library. Find Instagram, then press and hold on the icon. When the context menu appears, select "Move to Home Screen".

Sorry for the duplicate, Lawrence!

Go to the App Library (the last page of your Home screen), hold your finger on it, and choose “Add to home screen”, or drag it to where you want it on the Home screen.

You are pressing on it. Just hold your finger lightly on it.

If you can't find the option, pressing and dragging it to the left will achieve the same result.