Keeping track of progress on the dashboard

Folks, I find it difficult to keep track of the lessons that I have completed. Is there a decode of the symbols used? For example the orange dot in the two o'clock position that can appear on icons? I find my self returning to the course only to repeat lessons I have already undertaken. Is there a help page that specifically deals with progress markers? 

To my understanding and experience, a full green circle shows on each lesson fully completed.  The absence of that shows the lesson is not completed.  That's it.  

Hi RobertH-0pwt,

To add to ChrisM108's response, the red dot indicates that there are some phrases marked as Hard in that activity (see screenshot below), and so might need to be reviewed.

I hope that helps!