When you first open Google Hangouts you’ll be met with a new and fresh interface. The app opens to a window that shows your current conversations. Similarly to Gmail, you can archive messages by sliding your conversations to the left or the right.
By sliding to the right of the app you can start a new Hangout with someone. In the New Hangout page, you’ll see the people that you most frequently contact, and below that you’ll see everyone in your Google+ circles. If you have a lot of people circled, this list is pretty gigantic. Thankfully, you can easily search for a name or circle you want to chat with.
Hangouts doesn’t use the green or grey dots that Google Talk used to identify if someone is online or offline. Instead, you can tell if a contact is online if their profile picture is faded or clear. A faded profile picture means your contact is unavailable, and a clear picture means they’re online. One downside is that Hangouts doesn’t support the “invisible” status like Google Talk did.
After opening a conversation simply slide back to the left to go back to your active conversations list. At the top right is a plus sign that lets you start a new hangout. Similarly to Gmail, if you want to archive a conversation, simply slide them off the screen. You can view them later in the archived hangouts section of the app or your “Chats” category in Gmail.