In order to install the addon, you'll want to make sure you have the latest version.
You can do this by heading over to your the PRODUCTS/SERVICES and clicking the VISUAL ACCOLADE SYSTEM.

You will then have a DOWNLOADS category under the overview. This is where any supplementary files and core files will be located.

Finally, you'll see the [CORE] files, at which case you will just click download button underneath it.

A RAR file will be downloaded, at which case you should extract the WOS-VAS folder.
Once you've extracted the folder, use your favorite FTP client to upload it to your server's addons folder. The final path to the WOS-VAS lua folder will be the following
garrysmod/addons/wos-vas/lua
You're all done! The addon has been successfully installed. We recommend configuring the addon for maximum efficiency.
