Channels are where you start sorting the content you would like to send to air. Right now three channel types are supported: Facebook, Twitter, and Instagram. Channels can be created for either a user's profile (where all of their posts will show up) or can be created for a search term or hashtag.
Channels can be created with the "Create Channel" dialog on the left side of the screen.
Facebook User channels have an extra option to hide posts that other users have posted to the Facebook page. This is helpful if you want to create a channel which is only your Facebook posts to your page. You will see this option when in the dialogue to create a Facebook User channel. Note: Only public Facebook profiles and pages can be created as channels.
To delete a channel just click the gear icon next to the channels name and hit "Delete Channel".