Hello!
Azure Classroom Labs allows you to set up virtual machines to run a classroom in the cloud. Examples would include Artificial Intelligence, Shell scripting, ethical hacking, and Database management.
I believe you might be talking about video chat, using Microsoft Teams. You can visit the Teams forums at:
https://techcommunity.microsoft.com/t5/microsoft-teams/bd-p/MicrosoftTeams
It sounds like pinning a video is the feature that you are looking for (video demonstration), however I believe this only applies to your view (and not other participants/students). The Teams forums will be a better resource for a solution in this case.
Edit: I've added this as a suggestion in our feedback channel. Please vote on this to increase visibility:
https://teamsfeedback.uservoice.com/forums/427395-internal-microsoft/suggestions/41361355-allow-presenter-to-pin-a-particular-video-screen-f