how to fix my brakes on a vw golf?

This really could be any number of things from worn pads to a faulty master cylinder, seized calipers, failed hoses, brake fluid leak etc etc. In view of the obvious safety implications of ineffective brakes I would strongly suggest you seek the assistance of a garage as a matter of urgency. If you are worried about the cost, ask for a quote before they go ahead.

Lee
May 2007