Hi!
Take a moment and create an account for yourself:

1. Pick a user name, password, email address.
2. An email will be immediately sent to your email address.
3. Open your email, and click on the web link it contains.
4. Your account will be confirmed and you will be logged in.

Some courses (like free classes) require an 'enrollment key'.
This is listed in the course description or sent through email after you sign up for a free class.