Unsure of how to get those .VMFs running? Here’s a quick walkthrough:
1. Make Sure You’ve Downloaded and Ran the Base Game(s)
For this example, I’ll be using Half-Life 2 downloaded through Steam. Make sure you’ve ran the game briefly, just to ensure that the game knows where all the asset files are.
2. Download the Custom Level
This should be a .VMF (Valve Map File).
3. Place the .VMF in the Game’s Maps Folder
The easiest way to get to here is through Steam. Right-click on the game in Steam, and click Properties. Then, go to the tab on the top named Local Files, and click on the button that says Browse Local Files. For Half-Life 2, click the hl2 folder, then the maps folder. Finally, drag the .VMF into there.
If that doesn’t work, or you’re just in the mood to click through eighteen folders, you can navigate to it in Windows Explorer. Go through C:\Program Files(x86)\Steam\SteamApps\common\Half-Life 2\hl2\maps, and then drag the .VMF into there.
4. Load the File in Hammer
Go back to the Half-Life 2 root folder. Then click bin, and then scroll down until you find hammer.exe. Open this, and select “Half-Life 2” for the game configuration (NOT Episode One or Episode Two). Then go to File, and then Open. If Hammer doesn’t open the maps file automatically, navigate back to it. Then select the .VMF you want to play.
5. Run the Game!
Press F9 to run. A small window with text running should pop up soon to show that the level is loading. If it gets stuck on a line that says either “PortalFlow” or “BuildingFacelights”, or the window says it’s not responding, don’t worry! Just give it half a minute, and it should carry on soon. If it starts taking longer than that, consider running it on a more advanced machine, or telling the designer that their optimization sucks.
The game should start soon after. If weird things start happening while playing, contact me at firstname.lastname@example.org, and I’ll try to help solve the problem. If everything runs fine, then have fun!