Creating channels that allow users to contact each other is really simple. Just go to the Community section and click on the big plus above the channel list.
Clicking there will transfer you to channel creation page - just add a name and short description before you go into its settings.
In the settings you can decide who can see and add posts, who can join the channel and if it's visible on the channel list. You can also add groups of users to the channel.
List of all the channels is visible in Configuration/Community.
You can add new channels there and also edit those already existing - just click on the name.