Bruv, to disable CSM you usually need to first disable Secure Boot in BIOS. Look under the ‘Boot’ or ‘Security’ tab depending on your BIOS version. If you can’t change boot options, try resetting BIOS to default or updating BIOS firmware. Also, make sure to switch from Legacy to UEFI mode after disabling CSM. If you get stuck, hit me up and I’ll guide you through