You have decided to lock assignments, even when going to them directly via the assignment tab, as long as a student hasn't gone through all the lessons in the lesson tab. This is extremely confusing as it wasn't clear to me I had to unlock the lessons first over in the lesson tab. I kept going to the assignment via the assignment tab (because that really makes most sense to me when I want to submit an assignment) and there was no submit option. This led me to believe I didn't have to submit anything and led to a late submission after the teacher told me I hadn't submitted anything. This is a bad UX.
Please either leave the assignments on the assignment tab unlocked OR make it much more clear that they are locked due to the fact that the lessons haven't been viewed yet.
The teacher also didn't know what was going on when I told her I could not submit anything. And I was stuck, I couldn't submit until a week later I accidentally opened the lessons on the lesson tab up, and noticed FINALLY I was able to submit also on the assignment tab.
When I talked to my school, they don't even want these lessons and assignments locked at all. And the teacher didn't know it was locked nor that this is a setting she can change. This all needs to be much more clear.