Need help for summer camp using MS Teams

Organizing summer camp for school students;  from various department planning to engage around 600 school students from different schools of UAE;  suggest all the students given their Gmail and yahoo etc. mail ids.   how to conduct sessions for them expecting in one session 195+ students how to use teams for this purpose;  all users are not organization they are holding their gmail or yahoo IDs.  will the able  to see our meeting with camera facility or they can listen only our voice.  need a help

Regards

Jawid.M