As usbreset and bootmorphos most likely refer to commands found in X5000's UBoot firmware, it should be pretty simple. bootmorphos should allow you to boot into MorphOS via any available media as long as the MorphOS specific bootloader is found on it. If you press space on startup, it should also give some sort of graphics bootmenu where you can select Start MorphOS from the available options.
If the optical drive and the inserted bootmedia is properly detected, it should boot from the MorphOS CD right away.
If you already have a drive with MorphOS installed it should offer you some simple text menu to choose booting from optical drive or HD/SSD where you should select the optical media to update the system.
OK your information is apropiate and cool to me but I don't remember at all how I booted last July this year I think it was with a USB pendrive inside one of my X5000s USB ports.
If you know (that you may probably) just tell me how to boot my CD-Rom if you know that I think yes because you have more experience of this Morphos system than I and I really need help on this Amiga task.
Thank you and cheers