Navigation tip: when you first go through the project, you must hit the 'mark complete' button, at the bottom of the page, to unlock the next lesson. After 'mark complete' has been hit, you've unlocked that lesson, and you can then use the sidebar to easily click to different lessons within the project (helpful if you are working through the project with more than one class).
Why do I need to hit mark complete? Certain lessons have email triggers (such as teaching tips when there is a painting lesson), and this helps us know when to send them. It also helps us track completion rates.