It's really pretty complicated, Awasoda. Despite the reputation of Teutonic efficiency, the Germans did everything relating to armor in an overly-complicated way. The suggestions that you get some basic books are good ones.
The Germans started the war with dark grey tanks. This was generally not good. What was good was the way that dust would coat the tanks, and break up the sharp dark silhouette they had on the battlefield.
When they sent tanks to the desert, they actually painted them a light brownish color. Between this experience and the better protection of the dust, they realized that tanks were probably better off with at least some light brown or tan on them. At first, this was sent out as a color and painted ovver the grey, in patterns of various kinds. This was largely up to the units or even the individual vehicles. They put patterns on the tank in an attempt to break up the silhouette of the vehicle, so it was a bit harder to see at distance.
Later the tanks started coming out of the factory in the tan ("dark yellow") color. They would go to the front that way and the tank units were provided with green and or brown to put over the tank in waves or blotches. Ideally the tank units were to get both the dark green and the dark brown. Earlier, the green or brown were applied in squiggly lines, but as the war wore on solid blotches of color seem to have become more popular, but you see both right up to the end of the war. Sometimes the colors were applied in the factory, though. Henschel did this, and many of the Tiger IIs were painted with a standard three color scheme in the factory. This often included little V shapes painted over the solid blotches. This is called ambush scheme.
Finally, as stocks of paint wore out, they replaced the dark brown with the red primer coat (if you get my drift), and provides more limited amounts of dark yellow and green to put over it in patterns. Some very late war tanks are almost all red primer, with just a little yellow and green.
In the last gasps, they painted the tanks in whatever colors they had, including old stocks of panzer grey. Then, thankfully, they lost, and didn't have to worry about painting tanks any more.
This is a huge simplification. One thing to keep in mind is that the patterns were often applied at the front, not in the factory, so they would sometimes be crude brush strokes, sometimes well-applied airbrush patterns, and sometimes very peculiar patterns indeed. The books will bear this out. The absolute best thing is to get a photo of an actual tank and use that as your guide -- the limitation being, of course, that the photos are alomst all black and white!