Want to add some of those kit-of-parts electronics to your Elegoo but have no idea where to connect what?

Start with this introduction to the Arduino Uno Pinout: https://www.circuito.io/blog/arduino-uno-pinout/

Additional Hints:

• “Pinout” means the mapping of physical pins to internal microcontroller functionality.
• Many pins can do more than one thing. None of them can do everything.
• The I/O expansion board in your kit will give you 8 more inputs/outputs. It connects to the Arduino over the I2C bus (using up two more pins!).
• The Elegoo kit uses up almost all of the pins on the Arduino. You’ll have to get creative and make trade-offs.