This seems to work fairly well. If you can, try and bring enough nets for half of your group. Once you have a crab in a net, it needs to be transferred to a holding container. The simplest containers are buckets and they present no problem when working in pairs. If working alone, the bucket can be a problem.
Crabs are fast and both hands are needed to make a catch.
One important caution. Novices, young and old want to fill the crab bucket with water. The amount of water in the bucket is small and does not contain much oxygen. The crabs will use it up very fast. Like other animals, without oxygen they die.