Background operation - if enabled, you can continue capturing photos and videos even while you are using other applications, or other screens in Voyager. When the main screen enters/exists background mode, a new video recording sequence is started, thus the specified video length is not preserved.
The other settings here mainly control the placement of the Video/Protect/Photo buttons on top of other applications, allowing you to place them even at pixel-level resolution, so they don't get into the way of using your other in-car apps.
Warning! Starting with Android 6.0 (Marshmallow) the "draw over other apps" option is disabled by default in the main settings of the device. Please enable it manually via this route: Apps -> Settings icon -> Configure apps -> Special access (the wording may differ on various Android versions).
The Video/Photo buttons can be used the same way as the buttons from the main screen, and they also indicate the status of the video and photo operations. The Protect button works as the viewfinder on the main screen, allowing you to save away interesting road events.
The move button (with the arrows) allows a drag&drop operation on the whole group anywhere on the screen, so you can quickly uncover important areas from other apps.
A long-press on any of the buttons will take you back to the main screen, without affecting the video and photo operations.