Get on a level serface.. somewhere where the car won't move when you let off the break. Push down on the clutch, put the car in first, don't give it any gas, slowely let off the clutch until you start to feel the gears catch/engine bog down, and hold the clutch right there. now slowely start to ease out on it some more (still no gas) and the car should begin to start to move forward. You've just found where the catch point is. Do that a couple of times until you can do it smoothly, and slowely work in giving it gas.

Hope that helps.