To ensure your son/daughter does not miss any of their live classes, they need to accept the invitation from their teacher. To do this depends on the type of device you are using. It is different on an iPad Vs Laptop/PC Vs Smartphone.
You need to click on your Calendar in your TEAMS App AND accept the invitation by clicking RSVP. If given the option to ‘accept series’ you should select this.
Please email email@example.com if you need further assistance.
These pictures may help you.