I am a first time pc builder, and i'm wondering how i'm would get wired internet because my router and modem are in a another room across my house? Don't really wanna use wireless because its slower. Thanks.
It's all a bit tricky. Personally I prefer cable anytime. But if you're either going to need a long cable and / or drill holes that might not be the best idea.
Homeplugs or powerline I've used too and it worked a lot better, but as far as I know only if your room is on the same powergroup as the one your router is on. I'm not sure how powergroups in a house work in other countries, but in NL a house usually will have multiple ones in case of a powerdrop somewhere, the rest of the house might still have power.
Wifi can work great, but in my experience only if a) the walls aren't blocking signals (which may happen) and b) if there aren't too much devices connected compared to how much power it can deliver. My wifi was absolutely terrible, but my home as big walls and eventually there were arround 16 devices connected to a single wifi hotspot. Doesn't work too well.
EDIT: It mainly depends on what options you have. I wouldn't recommend cable if you're going to drill holes in places you don't want to, but I wouldn't recommend wifi either if the signal is being overused by devices. If it's one of those 2 I'd go for wifi and look if you can get a better signal or find a way to place a cable.