Your Raspberry Pi needs an operating system to work. Raspberry Pi Imager provides a range of built-in options including the officially supported operating system, Raspberry Pi OS (previously called Raspbian)

For the full Headless Plex tutorial we’ll elect to use a Headless, or Lite, version of this same Operating System, but if you’re not following the full Headless Plex guide go ahead and pick whatever is right for your project.

• Get Raspberry Pi Imager

The Raspberry Pi Imager download will be a .dmg file. Go ahead and double click that file, the drag the icon into your applications folder to install the application.

Imager will come in handy for future Raspberry Pi projects because it allows for quite a bit of up-front configuration using a simple, straight-forward interface.

Add the Micro SD card to your Micro SD USB card reader and plug it into your computer.

This should boot automatically, and you should now see a new drive in your Finder or file browser called boot or NO NAME

Launch Raspberry Pi Imager from your applications folder and click the button that says Choose Device, then select your device from the menu.

Now, click the button that says Choose OS, then select the operating system that is needed for your project.

For a Headless project, I usually select the option that says Raspberry Pi OS (other), then select the option for Raspberry Pi OS Lite (32-bit) or Raspberry Pi OS Lite (64-bit).

I typically use 64-bit for my Raspberry Pi 4 or Raspberry Pi 5, fwiw.

Back in the main Raspberry Pi Imager menu, click the button that says Choose Storage

You’ll want to select your Micro SD card from the menu. If more than one option appears, look for something called Generic- SD Card Media

Click the NEXT button, then click the EDIT SETTINGS button to pre-configure your Raspberry Pi OS installation.

Pre-configuring your Raspberry Pi OS settings will simplify accessing your wireless network on the Raspberry Pi and allowing access to the Raspberry Pi using SSH in the future.

You should write down some of these settings for future reference.

I recommend the following options under the GENERAL tab:

• Set hostname: (this will be used to ssh into the Raspberry Pi later, so you should write this down somewhere)
• Set Username and Password: You should also write the Username and Password down so that you’ll remember them later
• Configure wireless LAN: SSID is your WiFi network name, and Password is the password you use to access your WiFi network. Setting this up now will simplify your life later
• Wireless LAN country: Use the dropdown to pick the country code where you’ll be using the Raspberry Pi
• Set Locale listings: Again, use the dropdown to select the timezone where you’ll be using the Raspberry Pi

I recommend the following options under the SERVICES tab:

• Enable SSH → Use password authentication: You can use public-key authentication if you want, but for this tutorial we’re keeping things simple with Password authentication

Then click SAVE and when prompted click YES to apply the OS customisations.

A warning will apprear and ask you to confirm that you want to install Raspberry Pi Imager to the destination. Your Micro SD card will be erased of any pre-existing content. Click YES to continue.

You may need to enter your system password to write to the disk.

Raspberry Pi OS will now write to your Micro SD card. This might take a few minutes, so be patient 🙂

Once the installation is complete, you can unmount (eject) and remove the Micro SD card from your computer.

Put the Micro SD card into the designated slot on your Raspberry Pi, then power on the Raspberry Pi.

Now that you have your Operating System installed and your Raspberry Pi is powered on and running, it will be helpful to know how to SSH into the Pi from another computer.

In fact, knowing how to SSH into your Raspberry Pi will be an essential skill if you’re running a Headless Operating System.

Read our next guide: How To Log In to your Raspberry Pi with SSH or Secure Shell