Steps of installation

Agreements

• Temporary work dir = /install
• Squashfs mount point = /install/sqfs
• DestParts mount point = /install/dest

Mount targets

• Make new dirs to mount temporary recources(destparts, squashfs).
• Choose device for installation(/dev/sda e.g.).
• Prepare partitions. Use cfdisk(MBR) or cgdisk(GPT).
• Mount prepared root partition into /install/dest.
• Make subdirs(/install/dest/boot etc.) if nessesary.
• Mount prepared other partitions.
• Mount loop device(mount /dev/loop0 /install/sqfs).

Copying files

• Copy files from squashfs using rsync exclude /home/live.
• rsync -aHAXSr /install/sqfs /install/dest --exclude=/home/live e.g.

Chroot

• cd /install/dest
• mount -t proc /proc proc/
• mount -t sysfs /sys sys/
• mount -o bind /dev dev/
• mount -o bind /run run/
• chroot /install/dest /usr/bin/bash

Setup

• Write /etc/fstab(see man fstab, blkid).
• Mount /sys/firmware/efi/efivars to use EFI.
• Regenerate initramfs using dracut.
• Install grub( grub-install --force /dev/sda e.g., see man lsblk).
• Write grub config( grub-mkconfig -o /boot/grub/grub.cfg e.g.).
• Remove uglyside user.
• Create user.
• Make sure /etc/inittab is a symbolic link to inittab.install
• Exit chroot.
• Unmount temporary resources.
• umount --recursive /install/dest
• umount /install/sqfs
• umount /dev/loop0
• Reboot.

Also you can use Calamares installer.