On most Acer systems, you can use the F12 key on boot to select the drive or network from which loading the operating system. In case the F12 option does not work, you may need to enable this function.
Power on the system. As soon as the first logo screen appears, immediately press the F2 key, or the DEL key if you have a desktop, to enter the BIOS.
Press the right arrow key to select Main.
Use the arrow keys to navigate to F12 Boot Menu, and press ENTER.
Select Enabled, and press ENTER.
Press the F10 key to save changes and restart the system.
If the boot menu feature is not available in the BIOS setup menu, then the option is not available on your system.