I am an 8th Grader who is trying to make a mechanism involving a motherboard that can display LED Lights with an input from buttons and switches, do you have any tips on what materials I should get?
You'd need to learn how to code and how to connect things to the Arduino microcontroller, but there's lots of online help available.
If you need to stick to PC based systems, then you'll need an interface for the I/O. Something like this: https://numato.com/product/8-channel-usb-gpio-module-with-analog-inputs
You'll need to know some programming, including how to access the computer's serial port, since the namuto product emulates a serial port through USB.