As they are going to be thrown out forget what the plug says, you won't be using them all together!
Snip one off the wiring loom then attach a 10k resistor to one of the legs preferably the anode (+) this can be noted by a flat spot on the edge of the led itself, the legs will have been trimmed so are of no use in telling which is which. A 10k resistor is brown black orange then connect across a 12v battery, this will light it up, if it doesn't reverse the connectors on the battery it shoud light up. It will be bright, very bright or dim, the worse case scenario is it blows the led. If its too bright either stick another led in series with it or use a higher resistor.
This of course is if the led has two legs, if it has three or more than it is a multi colour led, ie red, green, yellow all in one 'bulb' and has to be handled differently.