You will need Protontricks, if you already have that installed you can skip this entire section after reading this.

Open up Discover and search for "Protontricks" then install it.
After that, search for "Flatseal" then install and open it.

Click on Protontricks on the left, scroll down to "Filesystem" then click "All user files" and give permission to /run/media under "Other files".

Before starting, run Muse Dash at least once with Proton 7.0-6 to generate the prefix.

Next Download .NET 6.0.16 Desktop Runtime[dotnet.microsoft.com]
Open Protontricks, then click on Muse Dash
Click on Select the default wineprefix
Click on Run winecfg
Go to Libraries and expand the box for Overrides, find "version" and then click add and apply
After adding it, come back to this menu and click Run uninstaller
Click on Install and then find your .NET 6.0.16 Desktop Runtime. Open it, install everything, and close Protontricks.

Install the MDMC Setup from the Muse Dash Modding Community Discord[discord.com]

Add mdmc-installer.exe as a Non-Steam Game, then click on the Gear Icon on the right, Properties, Compatibility, and set it to use Proton 7.0-6.

Launch mdmc-installer.exe through Steam, Click "Choose file" and locate MuseDash.exe.

Click "Install Mod Loader" and exit the installer once done. (You can remove mdmc-installer.exe from Steam now)

You should now be able to play Muse Dash with Mods and Custom Charts.

It's crashing on launch!
Make sure you followed all steps correctly, MDMC needs to be updated almost every update so make sure it currently supports whatever patch you are on. If all seems correct but it's still not working, uninstall the game, delete the proton prefix folder at steamapps/compatdata/774171, reinstall the game, and follow the steps closely. Don't be afraid to ask for help at the Muse Dash Modding Community Discord[discord.com].

Failed to Invoke Start Method!
Check your MelonLoader logs to see which Mods are causing issues.

Where do I download Mods?
At https://mdmc.moe/mods or the Muse Dash Modding Community Discord[discord.com].

How do I download Mods?
After downloading a mod, place the file in your Mods folder.

Custom Albums and/or Charts aren't appearing!
[Muse Plus] or [Just as Planned] are required to play custom songs because any song that is not in the Default Music album is considered a DLC song. You can use Mods just fine without any DLC.

Where do I download custom charts?
At https://mdmc.moe/charts.

How do I download custom charts?
After downloading a custom chart, place the file in your Custom_Albums folder.