Progress calculation for the whole course

Hi all,

All your suggestions are really appreciated.

The problem is as follows:

We are creating the different scenes that are uploaded separately from each other to our system in different zips. But they are all parts of the one course. So we have in result the course that consists of different modules (scenes).

My team aim is to calculate the user progress for the WHOLE course, not only for the one module/scheme. For the time being we've made to calculate the total amount of slides, but we don't know how to trigger where (in what slide) the user has left the course and therefore we can't calculate the user progress.

Could you please suggest how to trigger (using JS) where the user left the course and how to calculate the overall user course progress?