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+**WARNING: versions earlier than 1.5 don't support Wine/Proton at all.**
+
+To run version 1.5 or later of the Save Tool on the Steam Deck or another Linux machine where the native Linux version of Steam is used, follow these instructions.
+
+## Initial setup
+
+0. If you are on Steam Deck or any other machine where the desktop is not the default interface, switch to it. For the Deck, press the Steam button -> "Power" -> "Switch to Desktop". For Big Picture mode on other machines, click the Steam button or press the equivalent on your controller -> "Power" -> "Minimise Steam".
+   - Make sure you have launched M.A.S.S. Builder at least once, too, so its Proton prefix gets created and your saves get synchronised.
+
+1. Install Protontricks through Flatpak. If you are on the Steam Deck, use Discover. On other distros, use whatever frontend is available, or the command line if you don't have one. Some distros don't have Flatpak installed out of the box, and some of those don't preconfigure it to have the Flathub source enabled. TODO: add image.
+
+2. If you have a machine with multiple Steam library folders, like on a Deck with an SD card inserted, give Protontricks the ability to access that library folder using [the official instructions](https://github.com/flathub/com.github.Matoking.protontricks#configuration). For people not comfortable using the command line, I recommend using Flatseal.
+
+## Running the Save Tool
+
+### Option 1: using Protontricks' desktop integration
+
+1. Using the same instructions as step 2 above, grant Protontricks the permission to access the folder where `MassBuilderSaveTool-<version>.exe` is located. If you already did this, skip to the next step.
+2. From your file manager, right-click the executable and select "Open with Protontricks Launcher" or equivalent. On the Deck and other machines using KDE Plasma as their desktop environment, this may already be set as the default double-click action when Protontricks was installed.
+3. Select "M.A.S.S. Builder: 956680" in the list that appears.
+
+### Option 2: running Protontricks normally
+
+1. Launch Protontricks, and select "M.A.S.S. Builder: 956680" in the list. TODO: add image.
+2. When the Winetricks window opens, pick "Select the default wineprefix" and click OK. TODO: add image.
+3. When the second window opens (its title should contain "current prefix is" with a path to the prefix), choose "Run explorer" and click OK. TODO: add image
+4. In the explorer, navigate to where `MassBuilderSaveTool-<version>.exe` is installed, then double-click it. TODO: add image.
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