@MilkFlavorSalad,
“I want to learn Unreal Engine and just get some of these ideas in my head down on a game…”
Welcome to the journey :). Look up making a design document … to put your ideas into for scope and playability goals … but let’s say you’re graphically minded and typing out all that is not your thing … make a 2D layout first … progress to 3D, clearly denote goals, game play features, game mechanics, all drawn neatly. 
Have you tried the LEARN tab under UNREAL ENGINE on the website? I found this tutorial Creating a Level Blockout for Game Development (unrealengine.com) really made me think about the many hats a game/level designer wears and I began thinking about the big picture of beginning a game design in Unreal Engine. While he was talking though I was learning and planning out ways I would change it or how it would influence other ideas I have. I think that is the hallmark of a ‘worth your time’ learning experience. Many great tutorials on the Learn tab.
Practical advice:
I wish I had spent less time on learning with walkthroughs and how To’s. If you have a specific need for that feature in a game then learn it and implement it right away. it will be more impactful to your study and learning journey.
Another help is to think of your game in terms of repeatable small steps and objects and how you can create/borrow a framework/template to get started. EPIC provides many great free templates for you to sandbox or learn useful game development techniques.
Unreal Engine online learning has courses targeted to different jobs like animator, film maker, environment artist etc. etc. but a hobbyist is all of the above. Learn by spending time on the tasks in your interests that develop your skills for future fun projects.
Don’t try game Jams until your ego is ready for the experience.
You need a playbook and team mates and an environment to play, develop and game. You need some rules. Would be nice to have a coach or mentor. The community can help be coach albeit limited in scope.
You need to practice before the season starts.
Last, you need to play and have fun!
Additionally, if you have art in your head but are not an artist, I humbly suggest you hire/get an artist to create the art if your playability mechanic is good. If you want the experience … Blender is free with a huge community of support for making artistic assets. otherwise leave the art to the professionals. The reason I say that is because the many programs that surround Unreal Engine create a bottomless pit of learning and the mad skillz you desire to make the amazing dream thing you imagined will still belong to professionals after you sink hours into trying and learning. Those hours would have been better served working on your core mechanics of your game.
“To thine ownself be true” … soberly estimate your strengths and use the amazing Ecosystem Epic fosters in the community for Unreal Engine to bring your shadowed and hidden ideas to the bright light of creation so we all can experience the joy you uncover on your journey.
Spend 15 minutes day on your hobby if you’re interested.
Spend 30 minutes a day on improving your skills if you like it.
Invest an hour a day if after two weeks you have created and something.
Invest 3 hours a day if you love it!
Commit at least six hours a day if you want a new career in it!
Learning rewards you with recognition but creating something only you dreamed and dared to create is THE reward of a lifetime.
Best of Luck to you and all the creators, hobbyists and tinkers who change the world by caring to dream.