As a starter, to get the clutch pedal off the floor so you can shift:
Check to see that there is fluid in the Clutch Fluid Reservoir in the engine compartment. The Reservoir sits just behind the Brake Power Booster. The Reservoir is small plastic container with a black cap. The fluid for the clutch is brake fluid. You can add some brake fluid to the container. (Brake fluid can ruin paint so be careful of spills.)
When the fluid level is ok, you can manually push and pull the clutch pedal up and down. This will activate the Clutch Master Cylinder which is attached to and behind the clutch pedal. If the Master cylinder is Ok and if the Slave Cylinder (under the car next toi the transmission housing) is OK, the pedal should stay up as fluid fills the system.
If the Clutch Save Cylinder is leaking, the fluid level will slowly drop and the pedal will fall again. You will see brake fluid under the car below the Slave Cylinder location. A leaking cylinder must be replaced. It is also possible that the the Master Cylinder leaks (on to the car floor) or the inside rubber parts have dried and the Master might have to be replaced.
If the clutch pedal stays up, you should be able to shift if all else is OK with the clutch.
You will want to read the Tech Manual and messages on this web site about the issues you work on. Maybe a good idea to get a book (ebay or a used book dealer) such as the Haynes repair manual for your car. There is a page of Publications on this website that might help you find what you need.
Richard M, NYC