All analyses in MiGA @ XSEDE require login, but creating a user is easy and free. Simply enter your dashboard, and you will be redirected to a federated sign up / log in page. Click on Sign in with Existing Institution Credentials, and pick your institution.
Next, just click on Log On and follow the log in instructions of your own institution. You will be redirected to MiGA @ XSEDE once you have successfully logged in.
In order to log in, simply follow the same instructions above. You can also tick "Remember this selection", and MiGA @ XSEDE will remember your institution next time you access from that browser.