Okay, we'll start from the beginning. Ohm's law states that E=IR, where E is the voltage, I is the current, and R is the resistance. It's important to remember that current stays the same all throughout a series circuit--it never changes.
Voltage drop is the voltage "used up" by each resistor. You can use ohm's law to find the voltage across it if you multiply the current through the resistor by its resistance. So, the first thing you'll want to do is find the total current through the circuit. You can rearrange ohm's law to say that I=E/R. I is the total current, E is the total voltage, and R is the total resistance. Once you find I, you simply have to multiply it by each resistance to find the voltage drop across each of the resistors.
Does this make sense?