Clicking on your avatar (image icon) in the lower-left brings you to your Account page. Here, you'll see a summary of the Algorithms you've created -- at first, this will just be a default "Hello World" sample, and you don't need to worry about what these are unless you decide to learn how to create Algorithms. There's also a graph of your account balance (we'll cover this in a bit), and some helpful resources at the bottom.
For now, we'll skip over the "My Algorithms" and "Organizations" tabs (more on that soon) and head right to the "API Keys" tab.