How do I set up X Window System?

I am currently having trouble with X Window System. I have compiled and installed all of the packages, and I have installed tons of stuff to increase its compatibility with whatever programs BLFS recommends installing, but it won't work. "startx" fails, with the issue being "no screens found", and I have tried to edit config files, but to no avail. I compiled and installed the AMDGPU drivers, but if I enable them in the kernel, the system won't boot (this happens if GPU drivers are built as modules, or if they are always active). I am so confused right now, and I am really frustrated with this system.

Do I need to update GCC to the version in BLFS? Will that harm my system?

Also, what drivers do I use for a Gigabyte Radeon RX 590? What do I have to do to fix my GPU drivers for BLFS? It hangs on boot, but never at the same line.