Prerequisites

1. Raspberry Pi running RetroPie.
2. An active network connection on the Raspberry Pi.
3. Another computer on the same network for file transfers.

Steps

1. Access RetroPie Setup:
   • Boot up your Raspberry Pi and enter the EmulationStation interface (default interface of RetroPie).
   • Press Start on your controller and select Quit to get to the terminal/command line.
   • Type sudo raspi-config and press Enter.
2. Enable SSH (if not already done):
   • In the raspi-config menu, navigate to Interfacing Options.
   • Select SSH and choose Enable.
3. Install Samba:

   • At the terminal/command line, type the following commands:

     sudo apt-get update
     sudo apt-get install samba samba-common-bin
     

4. Configure Samba for RetroPie:

   • Edit the Samba configuration file using:

     sudo nano /etc/samba/smb.conf
     

   • Scroll to the bottom and add the following:

     [RetroPie]
     path = /home/pi/RetroPie/roms
     writeable=Yes
     create mask=0777
     directory mask=0777
     public=no
     

5. Set a Password for Samba:

   • While still in the terminal, set a password for the ‘pi’ user in Samba:

     sudo smbpasswd -a pi
     

   • Enter a password when prompted. This will be the password you’ll use when accessing the file share from another computer.

6. Restart Samba Service:

   • Restart the Samba service to apply the changes:

     sudo /etc/init.d/samba restart
     

7. Accessing ROMs Folder from Another Computer:
   • Windows: Open File Explorer and in the address bar type \\[RASPBERRY_PI_IP_ADDRESS]\RetroPie. Replace [RASPBERRY_PI_IP_ADDRESS] with the IP address of your Raspberry Pi.
   • Mac: Open Finder, click on Go in the top menu, select Connect to Server, and enter smb://[RASPBERRY_PI_IP_ADDRESS]/RetroPie.
8. Transfer ROMs:
   • Once connected, you can drag and drop ROMs into the appropriate system folders.
9. Return to EmulationStation:
   • After transferring ROMs, type emulationstation in the terminal of your Raspberry Pi to return to the game interface.
   • You might need to restart EmulationStation or the Raspberry Pi to see your new games.

Remember, always ensure you’re transferring ROMs you legally own. Enjoy your gaming!