When I engauge my clutch there is no pressure so it get stuck down and can't get it in or out of gear. I changed the slave cylinder and there is no change. The master is working fine so I am unsure of what it could be.

Have you Bled it? Plenty of fluid? How do you know Master is working fine? I had a Ford Van with stick shift and where the clutch master cylinder was mounted, metal got weak and "Flexed", I fabricated what I called a "pressure dispertion plate"? It stopped the flexing and solved the problem, may not be your problem.

Likely, there's air in the system and it needs to be bled.

It has only stopped while the new slave cylinder has been put in and I have bled the system but no change

It only takes the smallest amount of air for the pedal to go to the floor. It can be a very frustrating experience. Try to use a pressure bleeder.

When slave cylinder was replaced, any rods or mechanisms seemed to all go back in place? Plenty of fluid?

Yes all the mechanisms went back in place and I topped up the fluid but there was no change. Have not tried the pressure bleeder.