Left 4 Dead 2 add ons are .vpk files. Custom campaigns have to be installed on the server and on every player, because the server does not send maps to clients.
1. Get the campaign file
- Download the campaign, either from the Steam Workshop through your own game or from the author's site.
- You want the
.vpkfile itself. - Note the campaign's first map name. You will need it to start the campaign.
2. Upload it to the server
- Stop the server in the Game Panel.
- Open the Files tab and go to
left4dead2/addons. Create the folder if it does not exist. - Upload the
.vpkfile there. Use SFTP for large campaigns. - Start the server.
3. Start the campaign
- Open the Console tab in the panel.
- Run
changelevelfollowed by the campaign's first map name. - Read the console. A missing map is reported clearly, and usually means the file is in the wrong place or the map name is wrong.
4. Get your players ready
- Every player needs the same campaign installed, normally by subscribing to it on the Steam Workshop.
- A player without the campaign cannot join while it is running.
- Different versions of the same campaign cause problems, so agree on the workshop item everyone uses.
5. Server side plugins
Mutation and gameplay plugins that run through SourceMod only need to be on the server. Content that changes maps, models or sounds needs to be on the client as well. If in doubt, read what the add on page says it changes.
Add one campaign at a time and restart in between. Open a ticket from Support in the Client Area with the console output if a campaign will not load.





