There are way too many different details to give you step by step instructions.

You can get a couple of book on wiring. Two that I like are Black and Deckers Complete Home Wiring. And How to Wire a House by Rex Caldwell.

Then if you have a SPECIFIC question post it.

Or you can hire an electrican.

With the power turned off open the switch box. If there is only a white a nd ablck wire and both of them are connected to the switch then you CAN NOT do it because you do not have a neutral wire in the box. You have a switch loop.