Added arch update and snapshot info

ArchSetup.md

@@ -15,3 +15,25 @@ The wiki is wrong and your ${GRUB_MODULES} needs to be in ""
 5. Enable Secure Boot and import your MOK.cer into shim's MOK list.
 
 **Note:** If you ever re-install the GRUB `grubx64.efi` file (to get a newer version of GRUB for example), make sure to do so with the modules as described above, and you will need to re-sign the file with `sbsign`.
+
+## Bootable System Snapshots
+### Setup
+**Note:** For the below to work Arch must be installed on a btrfs filesystem with seperate root (@) and home (@home) subvolumes. (This is the default for EndeavourOS when you select btrfs.) And you must be using GRUB as your bootloader.
+
+1. Install the following packages:
+   - `btrfs-progs` - Utilies for btrfs
+   - `grub-btrfs` - automatically adds Snapshots to the GRUB menu
+   - `timeshift` - creates and manages snapshots
+   - `inotify-tools` - used by grub-btrfs to spot new snapshots
+2. Open timeshift and go through the setup, I recommend not including @home in snapshots.
+3. Run `sudo systemctl edit --full grub-btrfsd` and adjust the `ExecStart=` line to be `ExecStart=/usr/bin/grub-btrfsd --syslog --timeshift-auto`
+4. Enable grub-btrfs with `sudo systemctl enable --now grub-btrfsd`
+5. Install `timeshift-autosnap` from the AUR
+6. Edit the timeshift-autosnap config as desired, but be sure to disable it updating GRUB and that will conflict with `grub-btrfs`
+
+### Usage
+When you preform a system update a snapshots should automatically be created.
+You can also manually create snapshots from the timeshift program.
+
+If you boot into a snapshot or otherwise want to use a snapshot, first open timeshift and `restore` the snapshot you want to use (or are booted into) and then reboot. 
+This will properly restore the system to that snapshot.