I am a new user of the bare metal Linux system and I want to install garuda as my primary OS so for that my stupid gaming laptop bios has no legacy boot potion and has only a secure boot for that to work I need a properly signed image of garuda how can I install Linux with this issue?
This is right, no matter what you must disable secure boot to install Garuda Linux. There is no other way.
Legacy boot is something unrelated; it has to do with booting UEFI systems in the old BIOS-method, without an EFI partition.
You can enable secure boot after the installation if you wish and set up a shim that will honor the Microsoft boot keys, but it is not trivial to set up. I would consider it an advanced configuration. Have a look and decide for yourself if it is worth the bother: Unified Extensible Firmware Interface/Secure Boot - ArchWiki