tutorials to paint?

i have no idea how to do that…i only have different objects with different materials! how can i paint one object in 2 different colors/materials…
i heard it’s called uvmapping…right? but how do i use it? i dont think it’s in the basic tutorials!

I made a video tutorial here (45Mb about 20min)

The tutorial explains how to unwrap your mesh and export a guide for painting. Then you paint your texture in a 2d paint program and load it back into blender.