Hindi rin ako as techy pero kung zero idea ka talaga sa pagbuild may mga youtuber like Linus tech tips at pc centric, sobrang informative and may mga vids sila na gumagawa sila ng sample builds na affordable + easy to buy na parts. I think better na dun ka magtingin instead of me suggesting kasi maeexplain nila + a video helps kasi you can see what youre getting.
Yung specs it should depend sa main use ng computer mo, yung desktop ko before i switched to a laptop is focused on having more RAM gigabytes instead of a high end GPU. Yun ang ginawa ko because ang work ko is 3D modelling and higher RAM basically makes me render 3D objects faster and hindi stressed yung pc. I didn't really care much sa graphics ng games ko so a mid range GPU was enough to keep me going, the RAM helps with the gaming too kasi mas steady ang fps and lower chances of heating.