Signing in is easy! You can sign in using any Google account.
CrowdGrader relies on Google for login. The only information CrowdGrader uses from your Google account is your email address, which will become your CrowdGrader username. CrowdGrader has no access to your Google password, email messages, or other information.
Hint: if you sign in, and you cannot find the assignment you want, you might have signed in with the wrong Google account. To remedy that, sign out, and sign in again with the correct account.
If you are signed into 4 or more Google accounts at the same time, a bug may prevent you from signing in into CrowdGrader. Sign out of your other accounts, or use CrowdGrader via an incognito window.
If you sign out, you unfortunately sign out of all your Google accounts -- not just out of CrowdGrader (see this bug).