The grand march is exactly what it says on the tin!! Bride and groom start and walk round the room (however many times until everyone has had a good look!) Then mother of the bride and father of the groom, mother of the groom and father of the bride join in with bridesmaids and groomsmen and parade a few more times round the room. Then everyone else can get up and join in. This carries on until everyone who wants to dance (usually the whole company) has done a few turns.

Once the bride and groom reach the opposite end of the circle from the band they start the walk up the middle and everyone follows. The caller then makes sure everyone goes in the right direction, the bride and groom go to the left and the next couple to the right, the couple after to the left etc etc and they walk down the room to meet another couple and join up as a foursome. The foursome then walk up the middle and it happens again - they go to the left, the next fourseom to the right etc etc. Then obviously they meet up with the foursome to make an eightsome. Up the middle again and march on the spot until everyone has made up and eightsome.

You're then ready to do a set dance. Its a good way of mixing up the families too.

Apologies if the above doesnt make much sense, I'm not a caller (although i am a daughter of a gym teacher who teaches dancing every christmas time for the kids at school, so I should know better!!)

maybe a youtube search or something might make more sense!!