If you're that worried, connect everything up outside of the case first and test. At least then you'll know when you put it in that all being well, it should work.
I normally lay the motherboard on its box and connect as few components are needed to get a display.
Do what John said "connect everything up outside of the case".
It's called breadboarding. I've done it with all of my PC builds before I fully build them. I have to admit, I've been lucky and haven't had a problem except for once having to re-download the Media Creation Tool onto a Flash drive because the first one I did wouldn't install Windows correctly, but that's not hardware related.
Try not to worry about what will happen and think about what is going to happen as you build your PC.
It's fun, it's rewarding, and if all goes well, you'll be quite excited about what you just accomplished.
p.s. Have fun too!!!