Ohm’s law is how he wound up with those values. What you need to do is pick your power supply voltage, ie:9volts, then you calculate your load current= total of all your loads, as in the loads of leds probally have around NOKINA each, so you add NOKINA+NOKINA=6mA, you then convert mA to amps 1000mA=1Amp, in this case 6mA/1000= .006 mA You now have your Volts, and your ( I )Current, so Ohm’s law