IT is a pretty complicated task that is hard to describe. Especially not knowing the year of car. The process can vary a lot by year so you should go pick up a service manual and get detailed instructions with pictures.
Pull the wheel. Unbolt the CV shaft from the hub. Disconnect the lower ball joint and the outer tie rod. The shaft should be able to slip out now and be careful to not damage the ABS connections. Reverse order to reinstall.
If you are going to do it yourself I would advise you purchase a book for your car that would give you step by step diagrams on what to do. There is many mistakes that you could make if you don't know what you are doing.
This is a very tricky procedure that if not done correctly could cause more problems. My best advice to you would be to get it done by a professional mechanic.
