A couple of notes, with thanks to all the contributors to threads on fork maintenance: I've recently rebuilt the forks on my R65LS relying substantially on this forum.
These two videos are indeed helpful. Although there are a number of BMW fork rebuild videos on youtube this was the only one I could find that dealt specifically with my LS forks. One caveat (apart from the need for a language warning): he uses an air wrench to remove the bolts at the base of the damper assembly. This works, but isn't necessary: a 13mm socket on two extensions (one long one short) down the staunchion will hold it while the bolt is undone. Same trick on reassembly allows correct torquing of the bolt and crush washer. He uses the air wrench again on assembly, and says that it doesn't matter if it's not correct because the bolt is held in place by the axel. This is technically correct, but if the bolt comes loose I'd expect fork oil to dribble past it, maybe onto the brake disks.
He installs the spring before the slider: you need to put the slider on first, and bolt the damper in place, before installing the spring.