http://www.youtube.com/watch?v=O9x097QRXeAStart there, and then post any specific questions you might have.
A word of caution: Bitcoin/Litecoin mining is a very technical and relatively complicated process for the average consumer, and requires at least a base knowledge of computer hardware/software. If you don't know what you're doing, you could end up wasting money in a best case scenario, and destroying all your hardware in a worst case scenario.