Comparator question

I have a quick question about how comparators work. I just bought a quad comparator from Radio Shack (part number 276-1712) and I want to make sure I understand how it works. The 14 pin set up is as follows.
Pin 1: Output 2
Pin 2: Output 1
Pin 3: V+
Pin 4: Input 1-
Pin 5: Input 1+
Pin 6: Input 2-
Pin 7: Input 2+
Pin 8: Input 4-
Pin 9: Input 4+
Pin 10: Input 3-
Pin 11: Input 3+
Pin 12: Input GND
Pin 13: Output 3
Pin 14: Output 4

I'm not quite sure what I have to do if I want to compare two voltages and what happens when I do hook them up to the comparatpr (i.e. what does the output do to show me which voltage is higher). If anyone could give me just a quick crash course in how this comparator works I would appreciate it very much, thank you.

Take a look at the data sheet: https://www.electro-tech-online.com/custompdfs/2004/06/LM339.pdf

Here's a link to an OP AMP tutorial, which goes through the basics of a comparator circuit.