There are two ways to remove that unwanted channel.  I, too, had to look up how to remove a channel.

 

Method 1:

1) Go to the Channel Store on your Roku
2) Top row My Channels category you should see your added channels
3) Select (ok button) the private channel you want to remove
4) Select (ok button) remove channel option from the channel’s page

Method 2: (if you have new 12 button Roku remote with * )

Roku home screen, when you have a channel highlighted, you can press the Options button to remove that channel, rate it or view its description.

1) Highlight the channel you want to remove from Roku home screen
2) Select (*) on the remote which will display channel options
3) Select (ok button) to remove channel from your lineup