ok you have steem on an exchange like poloniex? or bittrex? if thats the case, its easy to transfer it over. basically , you type your steemit user name as the account name. and your memo (under permissions in your wallet) in the memo . this might help - https://steemit.com/steem/@cryptos/how-to-transfer-steem-from-poloniex-to-steemit-com

transfer a small amount at first just to make sure everything is correct