OK so they are just LEDs, with no built-in drivers. The simple way to drive a LED is with a series resistor, but this is very inefficient for high current LEDs such as those, and the actual current you get will vary with the supply voltage and the LED itself. You can make a constant current driver using a mosfet and a bipolar transistor, which gets round the problem of the current being variable, but is still inefficient (the excess power will be dissipated in the mosfet, which will need a heatsink). Preferably, these LEDs should be driven by a constant current switching regulator.