That's something to be aware of. You can't kick anyone out of a hangout so if you are just dipping your toe in the hangout water, you might want to start one that is known only to your best friends or family members. Each hangout has its own URL. That URL can be shared as a link to invite others. However, only Google+ users are able to join.
Or just join one that you see already in progress. Once you get comfortable with the idea, jump in and start your own. You can start a hangout from the stream whenever you want. You can either go to plus.google.com/hangouts or click the blue Start a Hangout button on the side of your stream.
Once you are in a Hangout you see a horizontal bar of video images of those who are in the hangout. Whenever someone starts talking, their video image pops up as the large image above the horizontal bar of smaller images. That way you know who's talking. You can mute their video or microphone if you don't want to see or hear someone (perhaps they are behaving badly or they've got noise interference or... ). You can also mute your own. It's nice if participants mute theirs if they're racked with a coughing spasm! You can unmute at any time. You can also text chat while in the video chat.
We did that yesterday in a hangout as we had a participant who is deaf. She lip reads but because her lag was so extreme she could not see the lips of those talking. So we typed in the chat window to help keep her up to speed on what was being discussed. I suggested that she consider starting a weekly hangout where she could teach sign language to anyone interested. I'd attend! She seemed to like the idea so today I'm going to write to her to encourage her to set one up.
I've been thinking a lot about the use of Hangouts and one thing I'd like to try is using Hangouts for family chats. My idea is to arrange a time and day (perhaps once monthly) then let siblings, nieces, nephews and kids know. They would all be in my circle called FAMILY.
So I would start the hangout and invite only that circle. Family members who want to join in could do so. It would be so nice to have all of us able to see and hear each other and even the grandchildren could gather around to participate with their parents. In effect you'd have a virtual Family Reunion. And my readers know how much I love Family Reunions!