GRUB is a multi-boot bootloader that is installed by default on most Linux distributions. Here's a quick breakdown on getting it working with Arch Linux.
Install the package
pacman -S grub
If you're on UEFI, install
efibootmgr as well.
pacman -S efibootmgr
Install the bootloader
Create a partition in the first 2TB of your drive. This partition must be FAT and at least 100MB. The partition table of the disk must be GPT and the partition should be set as an EFI System Partition. Mount this partition under /boot/efi/. Install the bootloader to this EFI partition by executing the following command:
grub-install --target=x86_64-efi --efi-directory=/boot/efi/ --bootloader-id=Arch
Create a partition for /boot/ in the first 2TB of your disk (ext4 is fine). Set this partition to
Active so it will be used for booting.
Install GRUB to the disk by executing the following command, replacing /dev/sdX with your disk's location:
grub-install --target=i386-pc /dev/sdX
Generate the config file
After the bootloader has been installed we need to generate the main configuration file
grub-mkconfig -o /boot/grub/grub.cfg