(rather than the bottom one) to connect to your PC, as it is the primary port for data transfer. Are you planning to flash new firmware unlock your bootloader once you get into Fastboot? How to Enter Fastboot Mode on ASUS Rog Phone 8
: If you need to access a deeper "Enter Fastboot" menu: how to open fastboot mode on asus rog phone 3
This is the standard method used when the phone is powered off. (rather than the bottom one) to connect to
Use Volume keys to scroll, Power button to select. To exit, select “Power Off” or hold Power for 10 seconds. Use Volume keys to scroll, Power button to select
To return to normal operation, select or Power off from the menu and confirm with the Power button . You can also long-press the Power button for about 10 seconds to force a normal reboot.
: Plug your phone into your computer using a USB cable.