What do you mean with a "correct" voltage divider?
One with the correct ratio and the correct absolute values.
I still wonder how a voltage divider can give me 5V if the 12V PWM is high and there is no current?
If you have a voltage and load it with a resistor, you have current. That is ohms law.
A voltage divider is one of the most widely used configuration of resistors.
Or less formally
https://learn.sparkfun.com/tutorials/voltage-dividers