I am thinking of using DC -DC module ( 9 amp) for 10 LEDs (3W) in parallel with the same setup you created in the video . I mean can I use that 12V 2A charger that looks like a laptop. I have one more question. Will the LEDs be safe to use and last long with 9A DC DC module?12V 5 amp Or 12V 10 amp charger would be better for 10 LEDs in parallel with 10amp DC DC module?
Welcome to the forum
I am assuming you are referring to the How to Drive High Power LEDs guide Tim made.
As Tim mentioned in the guide LEDs are greedy for current and need somebody to supervise them otherwise they will become gluttons and die a very early life. Most power supplies are made to regulate voltage, not current. So you need a power supply that has adjustable current limiting to power high power LEDs.
Sometimes specialty LED power supplies are referred to as LED drivers.
Can you add some links to the power supply modules you were considering so we can check if they will be suitable?