Hello there.
Well, luckily the internet is a gold mine for these kind of stuffs. I too had a hard time before as you are, considering building a custom PC can be very fun, although challenging at first. To combat these, all you need is KNOWLEGDE. If you think that you are still have much to learn about assembling a custom pc, I would suggest watching videos, reading articles and heck, even a crash course on how computer works. It might sound overwhelming at first, but believe me, it'll be well worth it.
Creating a custom pc is a beautiful art, so don't take shortcuts and put some effort in gaining wisdom.
Here is something to get you started, a youtube link that I find very informative and a good crash course for someone like you.
https/www.youtube.com/user/Techquickie
From here, I hope you'll develop the passion and the desire to know more about PC hardwares. I'm sure the rest of the community have something to help you out too. Goodluck