If you would like to have granular control over your build, and just want to make sure everything will be compatible, you may appreciate https://pcpartpicker.com/ . As far as assembly goes, I think as long as you get an anti-static strap you should be fine. If you absolutely don't want to have to put a processor in yourself (legitimate), consider going to to newegg and simply picking out a basic desktop with a good processor and just select a graphics card seperately, and you should be fine.