How would one go about using a 46V DC power source to power something which needs 36V DC using resistors?
Not at all.

Resistors by definition cause a voltage drop proportional to the current draw.

So, you can't use resistors to make a supply at 36 V for varying current draw.

What you're looking for is a voltage regulator: 


a linear voltage regulator converts the voltage difference (10 V or 6 V, depending on whether I believe your title, or your question text) to heat, and acts like a "self-adjusting resistor". It's not made of resistors, but semiconductor devices (transistors, mainly).
a switch mode supply instead charges the magnetic field in an inductor and releases just enough energy from that to its output that the voltage is stable at the target voltage.


Without knowing how much or how little current you'll draw, no definite recommendation can be made, but at 6 or 10 V drop, chances are you want a switch mode power supply, which is relatively complex in theory, but can in practice be built from a controller IC, inductor, a diode and a few capacitors.