I’d recommend starting with a very small-scoped project that has some of the features you want to learn. Some images, some choices, branching dialog trees, resources, etc. depending on what it is you care about, pick a couple of things to focus on and make it very small scale. It’s easy to get overwhelmed, so having a small working prototype of something beginning to end (esp. something you can put together in days to weeks, rather than more time) is good for learning and something you can be proud of and look back on without getting overwhelmed with over designing and never finishing. I’d also recommend treating the project as the first in a long line of cool games you can make, instead of your magnum opus—again, trying to be a perfectionist with your first game can be very overwhelming and lead to you eventually giving up instead of getting your first game done. You can always go bigger later.

If it’s programming itself you are intimidated by, you might want to look into Twine or other interactive fiction tools to start off with—these should allow you to easily make choice based stories without having to worry about learning a bunch of coding off the bat.

Most of learning is just picking something you want to do, and finding other peoples examples of doing it and seeing how they do it—whether it’s showing unique sprites or implementing an inventory. Through this you make incremental progress learning. Don’t be afraid to search for examples and troubleshooting.

(Most of this is generic advice, sorry if it comes across as too basic but not sure what level your at — a lot of this is the same advice I give to my starting game design students. But coming from someone who is in game dev now and does programming every day, most of my learning is just searching “how to do X in Y [language/game engine] and learning to dissect stack overflow, examples, and documentation, plus following starter guides for new tools/projects in unfamiliar with). I’m not sure if there are more structured lessons or tutorials out there for the kind of game dev you are interested, but that could be worth looking into and following if you are easily overwhelmed or feel like you need more structure.

Good luck!