O365 - Channel Overview in Teams
Channels for your team are found on the left hand side of the screen. Each team will have the general channel as well as any other channels you or the group owner have created. Channels will be titled based upon the information and apps that can be found within that specific channel. If the team you are a part of has numerous channels you can right click on the channels in the list and favorite ones that you want to always show up first.