How do you replace a Vauxhall Astra rear light casing?

open boot,left and right side there is a vented cover behind cluster,take off and you will find on each cluster assembly two large plastic knurled knobs,unscrew one at a time,the last knob hold cluster till loosened,pull cluster rearwards from body,disconnect multi plug(clips need to be opened)bulb assembly is unclipped from housing,refit do opposit to removal