How do I use/set up this LED light strip?
The strip has effectively three wires:


5V
Data (DIN)
GND (two black wires; one for the power supply and one for the controller)


The individual LEDs are almost certainly a variant of the WS2812 driver, which are commonly used in Adafruit's "NeoPixel" product lines.

Most projects that use these employ a microcontroller to generate and send color data. Arduino is probably the most common, though you could use any platform that can meet the timing requirements.

Adafruit has a collection of very comprehensive tutorials about how to drive these. Start with their NeoPixel Uberguide.