In your message, type the message according to your period. Once it receives your number, it will ask for your full name (unless you've used Remind.com before).
Send a text to 81010
Period 1: @mrsmoncu
Period 2: @mrsmoncur
Period 4: @mrsmoncure
Period 5: @c7ab5
Period 6: @1fbde
For example, this is what signing up looks like on your cell phone (this is period one's code).