How does dim sum work?!

As the carts go by, the people pushing them will stop, and offer you to dishes on their cart. If you want one, they'll put a stamp on your check in the appropriate area.

Most dim sum places break their dishes down into Small, Medium, Large, and Special. All small dishes will cost the same, just like medium and large. Special is whatever the price for that item is.

When you're finished they take the bill and count the stamps. Eg. 3 small, 1 medium, 2 large, and 1 special that was $7.95.

So it's more akin to those sushi places where the sushi goes by on a conveyor belt or little boats and you pay per plate.

Don't be afraid to ask "what is that?" Eventually you'll learn the Chinese names of your favorites.

Yes traditionally it is a Chinese buffet on wheels. Many dim sum restaurants should give you a card with squares printed on it, which are divided into different price ranges. After you get one dish that cost $2, the server would stamp once under the $2 section, or another server would stamp once or twice under $4 after you other food item(s) that cost $4 each. Even though the cost is not marked on it, the servers will know where to stamp, but you might have to be careful they don't stamp under the more expensive section by mistake. The cashier will sum up the card when you pay.

Some dim sum restaurants might have order forms like a menu on the table, you mark 1,2,3 etc. against each dim sum item and the server will deliver them to you. Most probably they will still use the stamping card.

All of the places I've been to keep track of what you take from the carts (by seeing how many of each items is left in the basket) and add it up and charge you at the end

Most Dim sum places is a pay per plate. Prices vary from small, medium and large.

Where small can be $2, medium $3 and large $5. Prices vary depending upon location.