Can you engage all the gears with the engine off? If so the likelyhood is that the gearbox has all its gears.

If the car has stood for awhile it may well be that the clutch friction plate has rusted onto the flywheel.

First make sure the clutch arm is moving when you press the pedal. There should be slight freedom between the clutch release bearing and the cover plate, so make sure that is adjusted properly, Ie you can feel the free play by wriggling the arm. The spring should be present to hold the bearing away from the arm, but it doesn'r affect the symptom you describe.

Now check whether the clutch is releasing, stick the car in gear, get someone to press the pedal and then push the car, if the engine tries to turn the clutch isn't releasing.

Patent cure is to warm up the engine, get the car facing down a gentle slope or on level ground, engage first gear, hold the clutch down and start the engine. The clutch should free with a bang.

MAKE SURE YOU HAVE PLENTY OF SPACE AND THE BRAKES WORK. IT CAN HAPPEN THAT THE CLUTCH DOESN'T FREE AND YOU NEED ENOUGH SPACE TO REACT AND STOP!