Google is your best friend.
Start with the basics, I recommend either C# or javascript. C# for Unity, Javascript for HTML5 games.
C# > Don't start with unity right away. Install visual studio and write a few console programs. There are _plenty_ of tutorials out there. A suggestion would be a simple multi option (A/B/C) story-driven game. Doesn't need to make sense story wise, but the intent is for you to get used to types, logic and syntax. After you learn and utilise classes, structs, methods, inheritance.. properly, you can look for unity-related tutorials, or some other engine.
Javascript > There are a lot of "engines", but honestly you can technically make a game with only buttons etc, like all those popular "idle" or "clicker" games. Think of a simple game and try to code it out. Once you are comfortable, check out one of the libraries like PixiJS. A slighlty different approach is to use electron or another wrapper to wrap the game in an executable so it runs as a windows app rather than a web app.
Anything else > Choose a simple project and utilise google to further yourself along. Don't follow step by step tutorials for complex things, but rather learn the basic things (like loops, conditionals, functions) and then google specific issues / types etc.