So I have a 1999 gas gas txt321 I just got it’s my first trials bike and I took off the clutch to have a look at it to make sure it was all sound then when I put it back together it won’t engage or disengage the clutch there seems to be no pressure at all I never messed with the master cylinder or any of the clutch side lines and it was working perfect before I messed with the clutch’s internals is there a trick to it or something I’ve never messed with hydraulic clutches before so any advise would be much appreciated 

The clutch pressure plate only goes on one way. Look at the spring towers. One has a notch it it and there is a notch or mark on the pressure plate.