Duolingo Schools > Assignment by skill
First of all i wish there is a better clear guide on using classrooms .. now my problem is that i'm choosing a skill as an assignment e.g (verbs) when the time of the assignment finished some of the students tell me that we did the assignemt why your telling us missed? so when does duolingo count the assignemnt? and another question in the students course progress, what about the colors of the circles and the check mark... and guide for that?
You are in the right place to ask questions now!
First question: Did your students already complete the assignment before you assigned it?
Some teachers are experiencing a bit of a lag between when the students do the assignment and when it shows up. The question has arisen that maybe it is the sheer and sudden volume of teachers and classrooms. Wait a day and then check again.
The colors of the circles: As the students progress, the circle will change from gray (they can't access it yet because they haven't done the prerequisites. You can unlock gray circles early with "Assignments."), to purple, to blue, to green, to red, to orange (I think -- I'm a little colorblind) -- to gold. Gold is the highest level. After a while, gold will "crack" to show the student that they probably need to review it to keep it in their long-term memory.
Hold on. I'll hunt up the guide. I have to remember where to click for it.
Regarding the colours of the circles, OP may be talking about the skill icons as they appear in the Duolingo for Schools portal:
This looks like a remnant of the old trees before the crown update. It's mentioned here and there on the forums and on Reddit that they represented the type of content the skill was focused on (basics, nouns, adjectives, verbs, ...), but with the current trees I think they're just for looks.