Webroom has to be one of the best free virtual classrooms for online synchronous teaching I’ve seen. It’s very easy to set up a class. Just type in your email address and name and the classroom launches.
Once the class opens there’s a very easy to work through on-boarding task that ensures anyone entering the classroom has the correct browser (Chrome works best) , sufficient connectivity, and has set up their video and audio so you can be sure everyone can see each other.
Once you are set up you can invite students by email or share the link to the classroom.
Webroom has a lot of really great easy to use features including really simple to set up breakout rooms for getting students into pairs or groups, screen sharing, an interactive whiteboard for sharing images and text, file sharing and best of all link sharing.