How to (easily) change channel?

I set up LibreELEC to provide content to the guest room TV while my mother-in-law is visiting from China. I installed all the stuff in the Chinese Content repository, specifically including the CNTV Live feeds.

The TV’s remote control doesn’t pass down the HDMI, I found, so I still need to acquire one for this purpose, or use a simple tablet app for that.

Once viewing some CCTV channel, I could not figure out how to (easily) change channels. Using my mini keyboard/trackball, I could find my way back to the menus and choose a different one, but even that’s not simple because the home icon is not present until I click the [X] in the corner first.

This is quite unusable by a non-technical person, a 73-year-old granny.

I need the “channel up/down” buttons to change between items in a list I set up for her. That should just work, period, the way a plain old TV did back in the day. At the very least, move between channels in the CNTV plug-in, and next-prev items in whatever the last menu was that chose the current content.

How do I make this simple to use?