Follow & read through my blog feed might help you!? :) There are several ways. The easiest/quickest (but for sure not the cheapest) way for me was buying BTC/LTC via Coinbase per CC or SEPA & transfer it on my Bittrex/Poloniex account where I can exchange it againt STEEM or SBD (btw, do you know the difference?). From there you can easily send it to your Steemit account's wallet with the Memo key. The How-To you'll find in my feed. Let me know if you have any questions!
We're all here to help as good as possible 👌