Why don't the clutch regain it's pressure after changing the master cylinder on a 94 Mit 3000GTand if I need to bleed the air out of the line how and where do I start to do this?

to bleed the clutch you have to pump the pedal several times and then hold it down to the floor and then open the bleeder you may have to do this several time before the pedal comes back
Did you bleed the air out of the system after replacing it?