The touch buttons on LG G5 are back, home, and recent by default (and SIM manager for the dual SIM model). To change these buttons and customize navigation bar on LG G5, do as follows:
1. Open the Settings app on your LG G5
2. Go to the Display tab and tap the Home Touch Buttons option under the Home & Lock settings. (If you are on the List view, go to the Display settings and find the Home Touch Buttons option, under the Basic settings)
3. There are 3 options under the Edit Home Touch Buttons panel: Button Combination, Color, and Hide Home touch buttons
3.1. Touch the Buttons Combination option and rearrange, add or remove the home touch buttons. Available options to add or remove are: Opening the Notification Panel, Launching the Capture+, QSlide, and SIM card manager
3.2. Touch the Color option and select a color from White or Black.
3.3. Touch the Hide Home Touch Buttons option, to specify to hide/show the touch buttons when a specific app is running. (for example you can specify to hide the navigation bar when your are using Google Chrome)