I converted to Leuven Templates a month or so ago myself.
I am network hardware guy (routers, switches, ACLs, etc) NOT a web programmer, HTML or otherwise, and known enough to usually really screw things up. Instructions that some provide may well make sense to those fluent in HTML/PHP, but my usual response is

.
I was impressed with the initial installation instructions, combined with the fact that there were tests to make sure the right version of PHP was available from your hosting company, and that I could build the site, testing, tweaking, etc., while my current webpage remained unaffected.
Read the instructions, take your time and even the person without any HTML or PHP knowledge can implement these templates.
My results can be seen at:
www.sunset-weather.com