Its a 2000 Toyota Celica GTS. My clutch is starting to slip. I herd that you

Hello! The adjustment for the clutch pedal is purely for adjusting free-play of the pedal travel itself, and won't necessarily extend the life of your clutch. The button below the pedal on the firewall is the clutch interlock switch, and is designed as a safety so that you cannot start the car unless the pedal is completely depressed. If the car is not starting after having disturbed the switch, it may have failed; it is somewhat old plastic at this point. The part itself is only $30, and it looks like the install isn't difficult, though space will be tight.