Three options are available: sign in with Google, get a one-time code by email, or get a one-time code by SMS.
If an email login code doesn't arrive when you request it, check your spam folder. For SMS codes, make sure the number you entered is exact. Codes expire in a few minutes, so if it's been a while, request a new one.
If you're still having trouble, contact us and we'll sort it out.