Select disk destination on app installation with keyboard
Once you have reached the screen that requests you to "select the disk where you want to install macOS using keyboard", to select the disk destination:


Turn "VoiceOver" on by pressing:  cmd + F5  (laptops might need to
use "cmd + fn + F5" 


Move around on a pane you are interacting with
by using the following:  Control-Option-Arrows (up/down/left/right) Example:  control + option + "up arrow"  --  You will move your selection to the next selection above... 
To select a sub-category (e.g. in a grid or table) use: 
Control-Option-Shift-Down Arrow 
To exit a sub-category use: Control-Option-Shift-Up Arrow



Source: https://discussions.apple.com/message/31115644#31115644