To be able to play the game properly, it's best to have the Arma II: Complete Edition Pack available on Steam, which includes Combined Operations (Arma II and Operation Arrowhead) and the expansions British Armed Forces and Private Military Contractor.

In practice, you should be able to play by having only Combined Operations, but those expansion packs include HD textures which are used in the DayZ Mod, and thus, I recommend having them. For the sake of simplicity, this guide will assume you have Arma II: Complete Edition Pack. Without further ado, let's begin.


To run the DayZ Mod on Steam, you need to have both Arma II and Arma II: Operation Arrowhead installed in your system, you should also install British Armed Forces and Private Military Contractor, which, while not necessary to start the Mod itself, you'll want to have for the textures and to evade a few troubles, as some servers might require them.
Next, you'll install DayZ Mod from Steam.
And then, you'll download and install DayZ Launcher[dayzlauncher.com].

Once that's done, give yourself a pat in the back. You earned it.

Now that you have everything in place, you'll want to follow the next procedure:

• Open Arma II, wait for it to go to Main Menu, and then close it.
  
• Open Operation Arrowhead, wait for it to go to Main Menu, and then close it.
  
• Open DayZ Mod, wait for it to go to Main Menu, and then close it.

When all that's done, you'll open DayZ Launcher, and browse for a server. Take in mind a few tips:

• You'll want to press the "Ping" button on the top side of the Launcher. That way you'll sort the servers by their latency, and be able to choose one with a low ping (green) to have the best performance.
  
• If you're a new player, you might want to look for a server that has 20 or less players online, since you know how it is with these kind of games.

After you've found a server, you'll see there's 3 buttons in the server's nametag. The first one is to refresh the server, to see if someone else has connected, and to check the ping. The second one is to see the players' list for that server. And the third button is the one you'll use now.
Click the third button, and yet another download will begin. You can see the progress if you click in the "Mods" button in the top-left side of the Launcher. Once it's done, you'll want to restart your PC.

If you followed my instructions to the letter, there might a chance you can press the third button in the Launcher (in the server you've chosen) and you'll get a Steam message telling you something about launch options, in which you'll press "Accept" or "Yes" and Operation Arrowhead will open. Then, you go to "Multiplayer", press the "Remote" button, and you'll see there's an IP and Port (the ones for the server you chose in the launcher), just click connect and wait. If you manage to join, then congratulations, this guide is no longer useful for you, and I hope you have a lot of fun playing DayZ.

If, in the other hand, you did not manage to connect properly, bear with me, for I know some fixes.

This one is pretty common. If you're using Windows 7, then search for "CMD" on the start menu, and open CMD with admin privileges; when prompted for permission, press "Yes".

Write the following in the CMD box:

• bcdedit.exe -set TESTSIGNING OFF

If you're using Windows 8 or 10, write this instead:

• bcdedit /set TESTSIGNING OFF

Restart your PC after you've done this. Keep in mind this error will appear when trying to run Arma II: Operation Arrowhead, and will prevent you from playing in BattleEye-required servers.


This error appears when you, after going through all the procedures, manage to join a server, and the screen goes black with an ominous "Session Lost" message.

There's 2 ways you could be getting this one. The first way implies you're using the DayZ Mod game instead of Operation Arrowhead to play DayZ. While it may sound counter-intuitive, the Launcher will open Operation Arrowhead with the launch options ready to play if you use the "play" button in DayZ Launcher.
There was a guide telling people to copy the IP from DayZ Launcher and paste it on the Multiplayer > Remote inputs, but somehow that doesn't seem to work. Thus, you'll never be able to join a game.

The second way seems to have something to do with an "AddOns" folder in the Arma II directory. Go to Steam, Arma II > Local Files > AddOns folder and delete a file called "corepatch_a2.pbo" inside of the mentioned folder. After that, move the whole AddOns folder to the Arma II: Operation Arrowhead local files folder.

That should fix it.

Once again, if you followed my instructions, you should, by now, be able to play. I can't give you any tips related to gameplay since I'm not either a great DayZ nor Arma player. This game is really complex, but I feel like the hardest things in life yield the biggest rewards. Of course, it might be the same with videogames, for that matter Dark Souls and some other games which have that "fame" (or infamy) about being really complicate have such a niche community of players who have taken a lot of time from their life to hone their skills.

I hope this guide has helped you take your first steps into this game, as much as I wish you to have a lot of fun. Who knows, we might even end up finding each other in a server, me telling you to drop all your things unless you wanna end up like a swiss cheese or something like that, iono, think about it.

Anyway, not much else to say. Thanks for reading!