I got confused...
Once I became a member I downloaded the Dashboard Plugin which then asked me for an API. Good so far.
When I entered my wpmudev credentials, specifically username and email address, it said that was already taken. So...
I created a new email account for myself and used that to get the API key. The only problem is that this new account is a free account - not a paid account.
How do I switch the logged in account?
As it stands, I can't get to the plugins I'm so excited about!