Did not receive prompt to enter API key on installation

I'm using this for the first time and was following the instructions to install the dashboard. One of the instructions was "After installing, you will be prompted to enter your WPMU DEV API Key" and it goes on to say that inserting this is necessary to enable automatic updates. But I was not prompted for the key. When I activated the plugin, I got a form to create an account but there was a 'already a member' link at the bottom so I clicked on that and logged in. On logging in I got the dashboard. Where do I enter the API Key?
I'm testing this on my computer(localhost) so I don't know if that has got anything to do with that.