If you failed to receive the email to complete your registration, please log into your account at live100challenge.org and then click this link: https://live100challenge.org/dashboard
At the bottom of the page under the 'Not Receive Email?' section, please click the 'Connect to PAI' button which will then direct you to PAI Health to setup your PAI Health account and sync your heart monitor device. Once that is completed, you will then be ready to participate in the Live 100 Challenge program.
As a quick note, some email servers have a tendency to block emails that are system generated like the email you failed to receive from the Live 100 Challenge program. Please review this article on how to "whitelist" emails from the Live 100 Challenge program so that these emails are no longer blocked during your participation in the program: https://live100challenge.org/help-desk/emails-not-arriving