To Join online video class you will need to download Zoom app
for your PC or Pone or Tab
For PC, the download page will look like this
For smartphones or tabs, you can download from App store
Once you logged in to student's "Champs IT system" with your details, you will see the green button on your class timetable for a particular session for that day. This button will appear just 10 mins before your class start time.
To join online class, you need to press this button.