You can use any software you want. Personally i use Slic3r & pronterface. But ideally you want a control panel for the printer and then print from SD Card.
In terms of the printer i guess you mean the Prusa i3? There are many forms of this printer around currenty (Box, Single plate, supported lasercut model (dont now name lol).
http://reprap.org/wiki/Prusa_i3
Also there is a step by step 3D Animated build guide somewere on the web but i cannot find the link
Idealy if your new into reprap try and find a build day in your area. i hand built mine just by using google and it takes a bit to get going if you dont have someone who can solve simple problems for you in seconds.