During the account creation process, you may be asked for an email address. Use an address you have immediate access to.
After you enter your email address, your screen will look like this:
Keep this window open.
In a different window or new tab in your browser, check your email inbox for an email from email@example.com with the subject Your ID.me account confirmation code. (You may need to check your spam folder.)
Open the email and click the Confirm your email link. (Or copy and paste the link from the email into the screen above.)