Mechanical numeric keypad. Help request

[Pul5ar]

I seem to have caught the mechanical keyboard bug and have decided to try and build my own mechanical numeric keypad as the rubber dome one I have is quite unpleasant to use.
Wiring the thing up is fine. I understand putting diodes on one side of the switches and wiring them in columns and rows. The problem I have is when moving on to programming. I intend on using a Teensy but I'm not sure about firmware. I have done some research and tried to make sense of matt3o's guide on deskthority, but I think it's far too advanced for me. The EasyAVR firmware seems the way to go for a beginner/non-programmer, but which pins on the Teensy do you connect the rows, columns and led to? I've been tearing my hair out trying to understand this stuff, and I feel I must be missing something. Some advice would be appreciated.

[suicidal_orange]

Any of the pins labelled [LETTER][NUMBER] (e.g B3 or C7) are good to use, just remember what's where to put in the firmware config.  For LEDs put them and their resistor between 5v and one of these pins to control it.

Oh, and avoid pin on the corner next to the LED on the Teensy 2.0, it's connected to the LED and causes problems if you use it for the switch matrix.

[Pul5ar]

I'm still confused. I made a layout based on the GHpad in the keymapper, but don't the rows and columns connect to a specific pin on a teensy or can you just solder them to any of the [LETTER][NUMBER] pins?