Installing a PSU is one of the easier things to do to a PC. Just line up the screw holes and screw it in. The power wires themselves are very simple because only the right connector will fit a socket. You don't need a ground strap. I've built over a dozen PC's without a ground strap and wearing socks. As long as you're in contact with the case you should be ok. Having said that, a ground strap is all of $5 and that's some pretty cheap insurance in my book.