You have a couple options!

You can enter your phone number on the first screen and you will receive a text with your code. (If you have unsubscribed from texts, this option won't work for you- check out email option below.)

You can also enter your email address on the first screen - in the spot where it says enter phone number (secrets - screenshot below). Once you hit Continue, you will be asked to enter the code sent to your email/phone number.

If you are experiencing issues, head back to the beginning and tap "Sign In", enter your email address and you will be good to go.