1995 Isuzu Trooper Clutch Pedal repair?

1995 Isuzu Trooper, manual 4WD:
I acquired this vehicle knowing that I would need to fix it to use it. I was told that the problem lied within the clutch cylinders or that it had a clutch-related problem. While working on the SUV, I noticed that the clutch pedal was not functioning properly: the pedal would either stay up (ready to engage) or all the way down to the floor (engaged). My concern is that there is no pressure or resistance when engaging the pedal (which, after engaging it, STAY down to the floor. It does not return).
I'm wondering if the problem just lies within the pedal adjustment or if the pedal is disconnected from a line or something of that nature. Is there possibly a missing spring that keeps the pedal in the "disengaged" position?
I should also note that when the pedal IS down on the floor, the vehicle will start and will not if it's disengaged. I'm wondering if that will contribute at all to any of the symptoms listed above. Thank you in advance for the help!