Here is how you and your students who have a Google sign on can sign into Tinkercad with your Google credentials.
1. On Tinkercad.com, click "Sign In".
2. In the next screen, click "Sign in with Google".
3. Then, enter your Google credentials to log into Tinkercad.
Note: Signing in with Google (or any social login option) creates a new Tinkercad account when you sign in for the first time.