The bamboo steamer is a multi-layer container that allows you to separate and cook different types of foods at one time. They layers have an open-weave bottom that allows steam to pass through to cook the food.
Your steamer needs to be placed over a pot of boiling water. While it is common to use a wok for this purpose it may not be the best use for your wok. Boiling water in a wok will remove your careful "seasoning". Unless you keep a special wok just for steaming then the best choice is to select a metal pot that is slightly wider than your steamer. Make sure the steamer fits far enough into the pot to balance safely.
You can lay food directly on the steamer layers but this will make for more work at cleanup time. To save yourself some work you can use a variety of materials to line the steamer. Some of these products made add flavor to the food so make sure you select one that will work well with the foods you are steaming. Here are some examples.
Place about 2 inches of water in your selected pan and bring to a boil. Sit the steamer layers on top of the pan. Fill steamer with foods per your recipe and place the steamer lid atop the steamer. Steam until your food is cooked. Be careful when removing the steamer lid as hot steam can burn. Use bamboo tongs to remove foods from the steamer.
Place a penny (or any coin) in the bottom of the boiling water. You'll hear the coin "jangling" in the pot as the water boils. If the sound stops you know you are out of water.
After each use rinse the steamer trays with warm soapy water. Do not allow them to soak for an extended period of time in water. Use a nylon scrubber (not metal) to scrub off any stubborn food bits. Do not place in dish washer.
Always allow your steamer to air dry before you put it away. This is especially important in humid climates because the damp wood may begin to mold.