Lift off the tremolo assembly, turn it over and unscrew the existing collet
Fit the Staytrem collet and tighten firmly.
Replace the tremolo assembly and six screws, tighten firmly.
Sometimes the existing collet can be difficult to remove, in this case it will be necessary to grip the floating plate in a vice to get more force on the spanner or wrench. Grip the plate as shown below and this will avoid damaging the chrome on the top plate.