outro: is it possible, some easy way, to limit the current other than changing the resistor?
Simple answer, no.
But you could go for the "remove R330" option to make it a 500mA module.
outro: Also, I am not quite sure how to use this? It has only GND + Vcc?
It certainly has not! It has two wires labeled "Led out" which go to the led. And at the other end it has two pad's for the supply voltage. It has a bridge rectifier on it so polarity doesn't matter.
outro: How can I control it with an Arduino?
Told you that already ;)
septillion: I think all these three are based on the PT4115 chip which is a very popular chip. Although most modules don't break the pin out (aka, don't add a solder pad) the chip does support dimming via PWM. Just solder a wire directly to the chip and it's a very easy driver.
It's pin 8 of the chip aka the one next to the word "OUT". You can connect this pin to an Arduino pin. And of course the led GND and the Arduino GND need to be connected.