why does my motor accelerate and the truck wont move?

What is your question?

motor accelerates but the truck barely moves, transmission shifts ok but seams not to engage, is this the clutch or the slave. and how do I know if I have a slave? the oil line from the clutch cylinder drops down and goes into the firewall can't seem to see where it goes from there. I'm not a mech. so where do I go from here?