Throw the net over the pier and be very amazed at your throwing skills. It is also advisable to check that the other end is actually tied to the pier before you actually throw the net over - other wise its bye bye net! Make sure the net actually sinks to the bottom because obviously thats where the crabs are!
Next step is to sit and wait. Come up with random games but do not be too loud so as to not scare the crabs away. Camwhoring and pretending you're superwoman is also accepted.
When you feel there are crabs in the net, usually about 10-15 minutes later, pull the net with all ur might. Be careful not to tip it over and thus saying goodbye to the delicious crabs. Be careful as they will snap at you. Good to have proper footwear (i.e. no thongs), a bucket with some water and engineering skills. Place crabs caught into bucket.
When you think the amount of crabs are enough to feed everyone,head back! Drive carefully and make sure the crabs don't spill out. Wash the crabs before cooking them. A vast variety to cook crabs can be found online. The best would have to be with noodles of course! :D
Finally, consume your hard earned crabs with a bottle of Riesling from the Barossa Valley.
THE END! :D