Depending on your specific device, your system may not be compatible with Linux. However, Google does provide both a list of supported devices, as well as a simple guide on how to enable it.
First, check if your specific device is compatible with the Linux system, here.

Next, Follow these steps to enable linux. Linux is off by default. You can turn it on any time from Settings.
1. On your Chromebook, at the bottom right, select the time.
2. Select Settings ⚙ > About ChromeOS > Developers.
3. Next to "Linux development environment," select Set up.
4. Follow the on-screen instructions. Setup can take 10 minutes or more.
5. Once it is finished, a terminal window should open. This gives you a Debian environment. You can run Linux commands, install Linux apps using the APT package manager, and customize your shell.

You may also want to enable Microphone access for Linux while you're there:
Assuming you're still in the Settings app,
1. On the left, select Linux.
2. On the left, select About Chrome OS > Developers > Linux development environment.
3. Turn on Allow Linux to access your microphone.

Finally, to get the linux version of MelonDS:
1. Go to the MelonDS Download Page.
2. Select the version of MelonDS for your system. This can be either the Linux ARM64, or the Linux x64 version. Which version is the correct one depends on your CPU Architecture.
3. Download and extract the zip file. Place the Extracted MelonDS file somewhere where you can easily find it back. For example: /home/YourUserName/MelonDS/ - or /home/YourUserName/Games/MelonDS/
4. Open the Linux Terminal and use CD to change to that directory:
(Note: Linux Paths are case sensitive! Remember the capitalization!)
5. This step is only needed for running the emulator for the first time: Mark the application as executable by running:
6. Run the emulator by typing


I hope this helps!
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