After you purchase a 1-year LearnToMod subscription, you should receive an email which will give you your Access Key and instructions about how create your LTM account and login to the site.
The Access Key email will automatically be sent to the email address you provided when placing your order. You should get it within 24 to 48 hours.
If you don't get this email, check your spam folder. Or you can contact support at email@example.com and ask for your Access Key email to be resent or forwarded to another email address. Let them know the email you ordered with, so they can look up your key.