Once you have installed Day of Defeat: Source, there are a few things you'll want to familiarize yourself with prior to playing online for the first time.
Setting your name
If this is the first time you have played Day of Defeat: Source, your name will automatically be set to "Player" - which will immediately identify you online as a new player. To change your name, go to the main menu and select "Options". Then, on the "Multiplayer" tab, change the name appearing in the box under "Player name". Click OK.
While the general controls are very similar to most other first-person games, there are a few unique controls in Day of Defeat: Source that will help greatly in the success of you and your team.
Joining a game
Find a server
Click "Find Servers" from the main menu to display a list of servers running Day of Defeat: Source. Find one that is running a map you want to play and click "Join". You can use the "Change Filters" tab to hide servers that are full or empty.
After joining a game and selecting a team ( U.S. Army or Wehrmacht ), you will need to select a class. Different classes have different strengths and weapons. Choose a class most suited to your play style and the features of the current map.
The primary objective of the game is to capture all the control points (flags) on the map. To do so, you must move to a flag post flying a neutral or enemy flag and stay near it until you've captured it. In some cases, this will require two players from the same team to stand near the flag at the same time. For more details, see Scoring.