You can deposit SBD the same way you would deposit STEEM. The important thing is to include your VIVA ID in the memo line, so we know to credit it to your account. The VIVA ID is the long number that you see when given instructions to make a STEEM deposit. Once you deposit your SBD and it's had a chance to clear, you will see it when you click on the VIVA/SBD market pair. Then you can start trading with it.