This part is easy: tap the Steam button, scroll down to Power, then select “Switch to Desktop.”

When the desktop environment starts up, you’ll use the right trackpad for cursor controls, R2 and L2 for left and right-click, and Steam+X to bring up the on-screen keyboard.

DOSBox is an emulator that runs classic DOS games on modern PCs and is easily installed via Steam’s desktop mode.

On the desktop taskbar, click the shopping bag icon to launch the Discover app store. Select the Startup section in the left sidebar, then type “DOSBox” in the search field at the top. Then click the Install button on the DOSBox entry.

To speed up the setup process, make sure all your DOS games are in one place. Click the folder icon on the taskbar to open the desktop mode file manager (called “Dolphin”), which you can use to organize your files.

For this guide, we’ll assume your games are stored in the Steam Deck Documents folder, in a subfolder called “DOS”. Each individual game should have its own subfolder within this “DOS” folder, with all the necessary files extracted.

Don’t have any DOS games yet? Internet Archive’s collection of MS-DOS games and MyAbandonware are good places to start.

Inside your DOS folder, right click on an empty space, then select Create New > Text File…

You will use this file to start one of your DOS games, so give it a name that is associated with the game and use .sh rather .TXT for the file extension. The exact name of the file doesn’t matter, but you could use something like “dukenukem.sh” for Duke Nukem as an example.

Now, we need to edit the startup .sh file to include instructions on how to start the game. But first, let’s copy the location of the DOS game .exe file to the clipboard.

• Navigate into the folder of one of your DOS games.
• Locate the .exe file that would normally launch the game. Usually this bears some resemblance to the name of the game itself.
• Right-click on the .exe file and select “Copy Location.”

Right click on the .sh file and select “Run with Kate” to open the text editor. In the text editor, type the following:

flatpak runs com.dosbox.DOSBOX ""

Now between the two quotes above, paste the location you copied earlier. Assuming your games are stored in the Documents folder, your text should now look like this:

Flatpak runs com.dosbox.DOSBOX "/home/deck/Documents/DOS/darkforces/dark.exe"

Click Save and close the file.

The next step is to make the game bootable from within Steam:

• While in desktop mode, launch Steam, go to the “Games” tab in the top menu.
• Select “Add a non-Steam game to My Library”.
• Select “Browse…”, then locate and select the .sh file you just created.
• Select “Add Selected Programs”.

At this point, the .sh file should appear in your Steam Library. Right click on it and select “Properties”, and you can rename it to the actual name of the game.

Now, you can start the game in Desktop mode to make sure it works, or just go back to Game mode.

Non-Steam games do not automatically come with artwork. If that bothers you, consider installing the Decky Loader and the SteamGridDB plugin to easily add art from the internal game mode. Alternatively, you can use SDGBoop to add artwork via desktop mode.

Back in Game mode, the DOS game will appear in the “Non-Steam” section of your library.

The game will most likely not work with the Steam Deck controls by default, and if they do, it is likely that they do not match modern controller conventions. That’s where Steam Deck’s extensive button remapping features come in handy.

When you’re ready to add more DOS games, return to Desktop mode, and then create a copy of your existing .sh file. Rename the game you are adding, paste the file location, and add the new file to Steam. Repeat this process for any DOS game you’d like to play on the Steam Deck, and enjoy your new vessel for PC gaming nostalgia.