Rent a carpet shampooer. Use very little soap and use only cool water. Rinse with clean water once cleaned. Left over soap in carpet will make it dirtier very fast.
The Rug Doctor system is readily available at many stores, the products you need are available for purchase. DIY stores also rent shampooers. After shampooing, rinse with cold water.
Kimberly....I use Blue Magic from AutoZone for spots...for whole carpet you can rent a machine.