In order to video chat in Facebook Messenger, you should open your messenger app and then search for the friend you want to talk to. Then you click on the video icon instead of the phone or other symbol. There are other features that can be used during the phone call. Besides, Facebook, you can also video call using several other different apps.
There is a way to video chat with multiple people in Facebook Messenger. You can video chat with a maximum of fifty people, but it will only show the first six. You will do that same as you would with one person, but then select the group chat members to include. All of those people can be part of the video chat if they accept the call.