This is a quick guide showing how to get a working version of the HL:A Hammer editor and tools (before Valve officially releases them). There's some limitations currently that need workarounds, so be sure to step in one of the Discord's below if you need help. Hopefully we'll get the official HL: A tools soon!
There is now a bat file that automates the instructions below. Download it here:
Note: make a backup first as you won't be able to play the game after doing this. You can either 1. duplicate your install to have a second copy dedicated to the hammer editor or 2. backup the folders you're instructed to replace and copy them back when you want to play.
If you forget to backup, just delete the folders you replaced and run the Steam "repair" and you'll be able to play again without having to download Alyx all over again.
C:\\Program Files (x86)\\Steam\\steamapps\\common\\SteamVR\\tools\\steamvr_environments\\game\\
(change the drive letter if you installed SteamVR or Alyx somewhere else except for the default location on c)
and copy the bin folder
Then paste it in your Alyx folder
C:\\Program Files (x86)\\Steam\\steamapps\\common\\Half-Life Alyx\\game\\
Choose "yes" when it asks you if you want to replace the contents