I am also having trouble trying to register
Your instructor should provide you with a 6-digit Course ID that identifies your active class section. Visit wileyplus.com and type in the course ID into the search field, and it will locate your class. If you weren't provided with this number, then you can type in the name of your school into the search field and from the results search for your instructor.
Once you've found your class section, you will be prompted to sign in (if you already have an account) or sign up. When you do this, you will be prompted to enter the registration code you purchased ahead of time, or purchase one then and there.
If you do not have a registration code, and are unable to purchase one at that moment, you can choose to use the 14-day grace period trial to access you class section (provided your instructor allowed for this).
Thanks for reaching out! I hope this helps.
Tom with Wiley