Simple! I sold all my wordly possessions to go all-in on steem. Sign up on any crypto exchange which takes fiat, then send them some dollars or euros, then buy some bitcoin. With bitcoin you can buy any crypto you like, including steem. You can also buy bitcoin with your credit card or from localbitcoins.

As you have noticed, the price of crypto moves alot. Some change 10% in minutes. For your safety I advise to use a “limit”, i.e specify the price at which you are willing to trade.