The clutch pedal is the leftmost pedal in a manual car. Pushing it down separates the engine from the transmission. This lets you change gears or stop the vehicle without stalling the engine. The pedal connects to the clutch master cylinder hydraulically or via a cable.
A soft clutch pedal means you have air in the fluid lines. If the pedal wiggles side to side, the bushings inside the bracket assembly are worn out. A pedal that stays stuck to the floor indicates a blown master or slave cylinder that can no longer hold hydraulic pressure.