Two major exchanges trade SBD and STEEM - bittrex.com and poloniex.com. As of the time of my typing this bittrex.com has frozen new account creation because of surge in demand / server overload, but poloniex.com is still accepting new members. In either case, you will have to jump through lots of hoops to include a picture of you holding your ID, hand writing out a statement saying you are signing up with date and signature, and giving up your first born son. One of those things may not be accurate :) The basic process is to transfer your SBD or STEEM to the exchange you have an account in, than trade it for a currency like bitcoin that is easier to turn into fiat currency. With bitcoin for example you can get a bitpay card which is a Visa debit card that you can load with bitcoin - the market price for bitcoin at the time you load the card is how much money you have to spend. Feel free to reply if you have questions :)