The Channels List shows all the Channels where you are a member. To help you find a Channel in the list use the search bar. Click on the magnifying glass symbol and start typing information that identifies the channel (channel name or part of description).
Public Channels are available to all users. Any user can search for and join any public Channel. To find a public Channel you may want to join, go to channel list page and click on Find button. In the search bar, start to type information that identifies the channel (channel name or part of description).
Then join the Channel you are interested in and click on Join button to save your choice. Once done, you will see the channel(s) in your Channel List.