Document downloading Windows SteamVR via SteamCMD

Also mention that firmware updates don't work for the 
Bigscreen Beyond Utility

content/docs/other/bigscreen-beyond-driver/_index.md

@@ -8,9 +8,29 @@ title: Bigscreen Beyond Driver
 You can get the "Bigscreen Beyond Driver" app from Steam working via Proton by following these instructions:
 1. use a Proton version >=10 that has access to `PROTON_ENABLE_HIDRAW` env var; `Proton Experimental [bleeding-edge]` works well
 2. set `PROTON_ENABLE_HIDRAW=0x35BD/0x0101 %command%` as your launch arg for the `Bigscreen Beyond Driver` under `Properties`
-3. OPTIONAL: copy a SteamVR Windows install somewhere in the prefix (ie: C/ root) under appid 2467050 and when the driver is open, set the SteamVR path to where you placed the Windows install of SteamVR
+3. OPTIONAL: download/copy a SteamVR Windows install somewhere and when the driver is open, set the SteamVR path to where you placed the Windows install of SteamVR
 
-The "Bigscreen Beyond Driver" and all of its features should be working fine after doing the above!
+The "Bigscreen Beyond Driver" and most of its features should be working fine after doing the above!
+
+Note that currently firmware updates do not work.
+
+## Download Windows SteamVR via SteamCMD
+You can easily downlwad the Windows version of SteamVR via SteamCMD. To do this:
+1. [Download SteamCMD](https://developer.valvesoftware.com/wiki/SteamCMD#Linux)
+2. Run this command somewhere you can create directories (i.e., your home directory):
+```sh
+mkdir steamvr_win && steamcmd +@ShutdownOnFailedCommand 1 \
+   +@sSteamCmdForcePlatformType windows \
+   +force_install_dir $(realpath steamvr_win) \
+   +login anonymous \
+   +app_update 250820 validate \
+   +quit
+```
+This will:
+- Create a directory in the current directory named `steamvr_win`
+- Download and validate Windows SteamVR into it.
+
+Note: your home directory is accessible under `Z:\home` by default in Proton.
 
 ## Easier Device Mode Swapping