I have an older guide that went in the other direction of steem --> bitcoin --> US dollar (using coinbase):
❓Answering Common Questions: How do I spend money from my Steemit wallet? 💲

I'm sure I can put one together tomorrow going from dollar to btc. I'd just have to get setup on the other available US wallets to step through them.

Lastly, I saw a lot of comments asking for a lay person presentation of what crypto is, so I thought this might be worth linking:
What is Cryptocurrency and Why It's Not Scary

I hope their helpful.