I had 18 yesterday and bought 45.50 steem with it. Check out this post and in the comments somebody layed out how to buy right from the platform and also where to check. Learned all of that yesterday myself lol. And didn't have the instructions yet. was pulling my hair a bit lol

https://steemit.com/crypto-news/@papa-pepper/what-your-mama-didn-t-tell-you-about-getting-paid-on-steemit-time-sensitive-information