The BIOS/EFI menu is skipped on all systems if there's something to boot, on most systems you need to hit some keys early to get into the firmware menu, often this is the DEL key or some F key like F12 or F8. The correct key should be displayed very early on in the boot, often at the bottom of the display. Otherwise, check your motherboards manual.
On EFI systems the GRUB menu has often a menu entry point named something like "boot into system firmware", if that's present you could try using that.