Type graphics in the Windows search box (lower left corner) and Choose Graphics settings. Browse for the program you want to use the RX560 and add it to the list. Click on the program in the list and choose options > high Performance. See below:
For the community, the solution that worked (at least in my case) is to go to Control Panel and open “Power Options” then navigate to find the “Switchable Dynamic Graphics” menu item then select Global Settings then set “Maximum Performance” for either “On Battery” mode or “Plugged in” mode which ever you prefer to use the desired GPU.