Progressive phases?

I am working on producing an online class that walks people through a series of steps and was wondering if anyone knew of a plugin that might be set up to handle something like this. For the online portion of the process, there will be a series of videos and written materials that students must go through in order. Example might look something like this.

Step 1: View video

Step 2: Review online written and/or downloadable content.

Step 3: Answer a series of questions.

Step 4: Action Steps

Step 5: Etc.

The process repeats itself through each of the four phases of the process. What I want is a system that will require them to go through each step before they can move on to the next. I.e., Step 2 is locked until Step 1 is completed. Make sense?

Anyone know of anything the would help with this?