Nowadays, 99% games are based on a game engine, so you have to choose a game engine like Unity, Unreal, and I suggest you choose Unity since its easier, and many people already built VR/AR projects with it, you can check on Youtube, tons of tutorials there.

Then you need get familiar with the Unity, and its language, then maybe follow a good step by step course, learn how to tackle each obstacle you will face later, if stuck somewhere, ask questions, learn maths or how to solve them, then publish your 1st game on App Store.

Good luck