Turn on your Mac by pressing the power button or by choosing Restart in the Apple menu if it’s already on.
Press and hold the Option (⌥) or command key immediately upon hearing the startup chime. Release the key after Startup Manager appears. Startup Manager will scan and list connected drives and volumes that can be booted from, as shown below.
Highlight the volume you want to use by using your mouse or trackpad or left and right arrow keys on the keyboard.
Double-click or press the "Return” key to boot your Mac from the selected “EFI Boot” volume.
Once selected the Secure operating system in ThinC-COMPUTE device will start booting.
