I did mine in a day. Removal is relatively easy - although the rear screws at the side are fiddly. Blue tack helps or a strong magnetic screwdriver or both. Removal of the old material is easy enough and cleaning thoroughly is important. There is some technique involved in glueing the new fabric down but a search through the usual places, ie here and Youtube will get you there.
Oh, and no point in cleaning it. The glue will in any case let go at some point and cleaning is only likely to accelerate the process.