Problem with progress bar

HI everyone,

I created a progress bar for my courses using the tutorial video from articulate. 

I created a progress meter fonction and like they say in the video I added a numeric variable +1 when you click on the last button of each chapter. 

The progress bar on the left works (see picture below). 

I would like to add a "completed" state to the each chapter when they are covered. 

It work if I add the status visited but the problem is than people can come back to this menu before they actually complet the chapter. 

How can I change both the progress bar and the status of the chapter on completed?

I tried to create a fonction for each chapter and like the prgress bar adding a numeric variable but it did not work. 

How did you do it in your video below ? 

http://learn.articulate.com/numeric-variables/

Thanks

Quentin