These are steps I had to take to get it working, all copied from the thread above. Hopefully it will help more nubs like myself!
Install snap-pac, snapper, grub-btrfs and btrfs-assistant
Open Btrfs Assistant
Switch to the “Snapper Settings” tab
Click on the “New Config” button
Name the config “root” and choose / as the mountpoint
Click the “Save Config” buttonSet the retention limits you want. In particular you probably want to lower the amount of “Number” snapshots that are retained. These are the snapshots that are taken when pacman runs. It takes 2 snapshots in each run so something like 10 is probably a more reasonable number. That will give you 5 pacman runs. The timeline settings are entirely left to your preferences.
Select the checkboxes for snapper-timeline and snapper-cleanup and click the “Apply” button to the right of the checkboxes.
Add support for booting off read-only snapshots
Edit
/etc/mkinitcpio.conf
and addgrub-btrfs-overlayfs
to the end of the HOOKS section
Rebuild your initrams withsudo mkinitcpio -P
Make sure the snapshots are added to the grub menu. There are two easy ways to do this. Only pick one of them
Enable thegrub-btrfs.path systemd unit
Create a file with the following contents at
/etc/systemd/system/grub-btrfs.path
[Unit] Description=Monitors for new snapshots [Path] PathModified=/.snapshots [Install] WantedBy=multi-user.target
Then type
sudo systemctl daemon-reload sudo systemctl reenable --now grub-btrfs.path
remake grub.cfg
grub-mkconfig -o /boot/grub/grub.cfg