Go to PC part picker and build your own PC there. Do some little reach on the parts you pick but honestly you don't need to know too much. Just look at the numbers (speed etc) they provide for each part on the site as well as reviews. The website automatically checks if all your parts are compatible or not. Built 2 custom PC's already using this site.
Used this video to help me assemble the computer. Second time I built my computer, didn't need it, it sorts of like lego essentially.