Connect 12V digital LED strip to Arduino
The datasheet isn't that helpful =(

But to power your led strip you need an external 12V supply, for that you can either:

Get a power converter (similar to phone charger) - Or battery - and power the arduino using it(through the arduino's DC 2.1mm jack).Then connect your LED strip to the Vin pin - not the 5V! - and ground the strip directly to the power supply since the arduino can't sink more than 0.2amps.

OR

get a power converter from a regular electronics store and just cut the wires and connect them directly to your strip.
Make sure you get one that can provide 12V and supply at least 0.6amp for every one meter of the strip.

OR 

you can get a 12V battery instead and connect them to the strip directly.

As for the Data line,there's not much i can help you with but it seems like your going to need to do some testing.

Someone please correct me if i'm wrong...

Power the LED strip and connect the DATA line to an analog pin and then increase the AnalogWrite from 0(0V) all the way to 255(5V). What you're looking for here is to see if it works on 5V or 3.3V. Or if the DATA line actually takes an analog input.