Pick a language. Write your tictactoe game. First write it in text output on a terminal. Get the gameplay working there. Fix the strategy/tactics/move evalu

Pick a language. Write your tictactoe game. First write it in text output on a terminal. Get the gameplay working there. Fix the strategy/tactics/move evaluation stuff there. Then make it use a GUI. Do the same with a snake game, but do it in a different language. Basically, you learn to code by coding. You already have things you want to do. So go do them. Start small (tictactoe) and try to write it. When you find you can't do it because you can't do console input? Learn console input, then go back to building the game. (That is, learn a little bit of console input - enough to get you unstuck on the game. Don't try to learn everything there is to learn, even about console input.)