Electronic circuit depend on voltage or current?

If the LED array is rated at 32 volts/3 amps, then the current limit is built in to the array. Simply apply 32 volts. The array should draw about 3 amps from the supply.

Does the LED array require 3A, or is that the maximum allowed current? If it is the maximum current, than a dropping resistor which is equivalent to 32 volts, minus the voltage drop of the LED array, divided by the effective resistance of the LED plus the internal source resistance, needs to be employed. If some of these values cannot be easily obtained, then you could safely start out with about 10 ohms, measure the current and then gradually adjust resistance until current is up to near the maximum safe current value. A potentiometer, of the proper current rating, and current meter should be employed to determine this.

Do not need the resistor if the 32v power source is regulated at exactly 32v output.