Here is a general guide for installing a hub motor kit:

http://www.eco-wheelz.com/kit-install.php

For the most part, if you have basic mechanical skills you can install a kit - especially a front-mounted one. Rears are a little more difficult since you have to deal with the gearing and derailer. You'd need a little more "bicycle skills" to handle a rear, but it's doable. Lots of help available online. Or, if you get stuck you could always call or visit a local bike shop.

ALSO, be sure you know what you need out of a kit. The one you referenced is slightly under-powered with a low capacity battery. If you just need assistance or don't have an extended range (over 6-8 miles) it might be OK. Otherwise, you may want to consider some of the other options out there...