Powering RGB LED strips using Arduino

So to preface, yes I've looked around the net at the various projects that people have done with this sort of thing. I have exactly zero experience working with Arduino as of this moment, but I have an Elegoo Super Starter kit and a bunch of TIP120 transistors, as well as a variable power supply and all the other necessaries. I'm just not sure where to start for the thing I want to do.

What I want to do is simple: power and be able to control (at least rudimetarily) a couple of different LED strips using my Uno unit to test them for power and brightness (using other equipment) for a larger project I'm working on. Only one strip will be connected at a time to the board, I'd just want to be able to test a few colors (R/G/B/W). What libraries/examples should I look at to get started on this?

I'd say start with the Blink app, make sure it works, then replace the single LED with your LED strips (via the driving transistor of course).

Look here (as well as google) on how to trigger/drive high current (power) LEDS...

Once you grasp the concept that a single Arduino pin can NOT driver/power anything more than a single accent led... and that you will only use the Arduino pin to TOGGLE the transistor which in turn toggles the external power source for the high powered led (strips)... things be easier!