Use this to remove and re-add a channel that is installed but doesn't appear on the Home screen.

1. Go to the Home Screen. Using Roku Remote, press Home at least 3x, then up 2x, then left, right, left, right, left.
2. After the Channel information Screen appears, scroll down and find the installed app that is not showing on your Home Screen and press OK, then select Remove.
3. Press Home to exit menu screen and then perform a System Restart on the device.
4. Use the Search feature from the Home Screen to install the app. (do not use online streaming store).

Source: https://community.roku.com/t5/Channels-viewing/Apps-not-appearing-on-my-Home-screen/td-p/1017333/page/3