When i have moved tanks i have bought some 5gallon buckets with lids. I use one bucket for the fish and another for the substrate, decorations and filter media.
Either use fresh declorinated water or the current tank water depending on how long they will be in the buckets (couple hours current water, 24 hours fresh water)
If they are going to be in the bucket for more than 24hours i would starve the fish for a couple of days before hand so they don't poo as much and produce
ammonia etc.. I have traveled fish this way for 48 hours or more and they have been fine.
Anna