You can convert using Steems internal market, exchanges like blocktrades or individual trading. But blocktrades offers less than the internal market.
Converting SBD to Steem is basically like buying steem for sbd. You can use any of the methods mentioned above but I would tell you to use internal market.. Its the one with least hassle for conversion of low amounts. And I'm going to give you a step by step tutorial on how you can do that..
First what you have to do is, go to your steem wallet. Scroll down to "steem dollars". Click/Tap on where it shows your SBD amount. A drop down menu will appear. Among the options you will see one labeled "Market". it will take you to steems internal Steem/SBD exchange. On the left side you will see a column labeled "Buy Steem" and on the right "Sell Steem".
Under "Buy steem" You will see three empty slots labeled as "Price", "amount" and "total"
Price is the amount of SBD you are willing to pay for every steem.
Amount is the amount of "Steem" you want to buy.
Total is the added amount of "SBD" you have to pay for the amount of steem.you want to buy.
Now fill out the form and click on buy steem. fill your credentials, click okay and you are done..
*The tables in the bottom shows the orders everyone listed. The "Price" slot will be automatically filled with the available current lowest ask. You will just have to input the amount you want. Or you can go for a lower price and your Buy order will be listed under SBD sell order.