Learning something new is difficult. You don't know what you don't know.
Here, I'll collect and link to resources that were helpful for me on my journey.
The Junior Programmer pathway is a easy introduction to C# whilst learning Unity Engine!
by Robert Nystrom. A fantastic book full of useful patterns you can use in your games.
You'll need to know some math to program a game. Freshen up on Trig and Linear Algebra.
Use your favorite programming language to solve puzzles.