This is my First Arduino project so bear with me.
This a simple LED Matrix that is run by an Arduino Uno 3.
You will need these parts:
-And some solid core wire
Step 1: LED placement
Place the LEDs across the middle of the breadboard one LED row on one side and one LED row on the other.
Place the LEDs so that each pin is in a different row on the breadboard.
Step 2: Grounding the LEDs
Then take small bits of the solid core wire and pin them down one the row in which each cathode is in. Take the other end and put it in one of the power slots. When you are done connecting all of the LEDs cathodes to the power slot connect the the two power slots with one long peice of wire.let yet another piece of wire connect to your Arduino.
Step 3: The positive leads.
Instead of just putting a jumper cable into the same row as the LED's anodes, I lead some wire out away from the LEDs on the breadboard so that I could attach the jumper wires to them. Away from the LEDs so that it would look better. This improved my project a lot I think.