Aquabid is pretty simple. You bid on a fish or if the fish has a "buy now" option you can choose that. After you win the fish Aquabid emails you with the contact information of the seller. You have to contact the seller within a certain amount of time to discuss payment and shipping. The best way to pay is through a paypal account. Many sellers ONLY accept paypal.
The seller will ask which transshipper you want your fish to go to. There are several in the US. After you choose your transshipper the seller will tell you when the next shipment day is.
You then must get in contact with the transshipper. Most of them have websites detailing how to pay them. (Here is an example from Jennifer Vivieros.. a transshipper near me...http://bellsouthpwp.net/J/e/JennViv/betttranship.htm
Once you pay the transshipper (I suggest doing this as quickly as possible) they will ship your fish out usually within 1-2 days of receiving your payment.