Blocktrades for that kind of transaction acts as the "exchange" so you did it right. You basically sold Blocktrades your SBD and bought STEEM, considering STEEM is currently cheaper than SBD you probably did okay. STEEM should be the token that eventually jumps in price and you will have earned a lot more for holding STEEM than by holding SBD.
Well done!
pocketsend:501@mikepm74, pocket all around!
Successful Send of 501
Sending Account: biophil
Receiving Account: mikepm74
New sending account balance: 908399
New receiving account balance: 480500
Fee: 1
Steem trxid: 641bcb7c36d5a58c3ab9ed8727cdefc6782d0b03
Thanks for using POCKET! I am running this confirmer code.