The first step: buy a good crab cage, which is available in the fishing gear market and not expensive.
Step 2: The crab cage can be unfolded to form a cylinder.
Step 3: Prepare the bait box in the crab cage.
Step 4: Put the bait into the bait box. Bait can be leftover shrimp skin, or you can go to the fish market and buy some fish intestines from the stall owner (usually a lot of money).
Crabs like fishy smell, and the bait should have fishy smell.
Fasten bait box
Tie the bait box in the crab cage.
Step 5: After putting the bait box in place, fasten the mouth of the crab cage.
The mouth on the side of the crab cage is easy for crabs to climb in and out.
Note that there are two ropes in the crab cage, because in case one section is stuck by a stone, you can pull the rope at the other end or pull it up. There are many rocks by the sea.
Step 6: Throw the crab cage into the sea (at a suitable distance and location, it is best that you have found crabs nearby).
Step 7: Tie the rope to the shore and wait for about an hour.
Step 8: The bait smells like fish. Remember to fetch a bucket of water and wash your hands.