Not sure how to control 4x4 sparkfun button pad, please help!

Hi there I’m trying to light/test a 4x4 LED sparkfun button pad that i put together.
Here it is:

My issue is that the instructions are for an arduino and I can’t find any help on setting this up for a raspberry pi.
Currently I am on exercise one and have soldered the wires to GPIO’s on the raspberry pi.
Now when I turn the raspberry pi on, the first row of red lights turn on but are dim.

Lots of info and code is included in the link I sent. It’s for an arduino though and I dont know how to apply that to a pi.

I just want to be pointed in the right direction of what I would code to even see if it’s working correctly.
I don’t know how to use pins or code at all. I just know that this is a matrix and that probably has something to do with how to code it. Does anyone have an Idea of how to turn all the lights on? Does anyone know how to tell the pi what to do with the gpio pins that I have connected?
Hopefully someone has used these pads before and could explain how to set this all up.

Here are the pins and what I connected it to. (Board numbers not BCM)
RED 4- pin 7
RED 3- pin 11
RED 2- pin 12
RED 1- pin 16
LED GND4 - pin 22
LED GND2- pin 37
LED GND3- pin 32
LED GND1- pin 36

If i already did something wrong, please let me know. I’m starting to think this hobby isn’t for me as I have no guidance, nobody to help and am completely lost. If you could help me on any of this it’d mean a lot.
Thanks for reading.