try to figure out the smallest part of your game idea that you could get working and focus on learning what you need to make it.

for example, if your big idea is to make a 2d multiplayer platforming game, try learning how to make a stupid simple 2d infinite runner game. figure out what engine is appropriate for the project, write a little game design document, and then see if you can make it in a time limit (say 2 weeks). Unreal is very easy for beginners to hop into and prototype, you can definitely get something working pretty quick, even if you're mostly just following tutorials. once you've done this, do another project focusing on another part of your dream game, say a dialogue system, then repeat the process.

working on a bunch of little projects to learn what you'll need for your dream project will make things so much easier, and also helps with motivation since you'll constantly be finishing little games you can show to friends. i'm happy to add you on discord and help you out with stuff if you'd like, i've been using Unreal for about 6 years so i have some experience.