A Team is a group of people gathered to get something done in your organization. As a city, we create a Group, which is a collection of things including a Team associated with it. See this article to see these relationships.
Teams are made up of channels, which are the conversations you have with your teammates. Each channel is dedicated to a specific topic, department, or project.
By default, all Teams have a General channel. This cannot be removed. It will also appear in Teams Files and cannot be deleted there either.
For example, the Northwind Traders team has General, Marketing, Overview, and 35 more channels. All the conversations, meetings, files, and apps in the Marketing channel have to do with marketing, and everything in this channel is visible to everyone on the Northwind Traders team.
Channels are where the work actually gets done—where text, audio, and video conversations occur and where files are shared. The communication that occurs on a channel is open to all team members.
While channel conversations are open to all team members, chats are just between you and someone else. Think of them like instant messages in Skype for Business or other messaging apps.
Private channels are a subset of a Team and have a private SharePoint site.
Here is a quick video that walks through setting up a Team and adding channels.
In the next article, we will discuss how to start collaborating within Teams and channels.