I have a trane VCMA-10/VCMA-15VCMA-20 Series. When I turn on the A/C on it starts to leak water from above, inside the unit. I can see the water dripping but not exactly from where. I also do not know how to drain the pump in case it is clogged.

If water is dripping you either have a rusted out drip pan or a clogged drain hole.Can you see water running into the condensate pump? Pump is usually on thefloor next to the air handler. If the unit is in the attic it gravity drains.