They are in dds format. But you don't have to install a graphic software that can handle dds for now. I used png pictures for this tutorial.
Overlay is not used in this tutorial. You have to make your Mask, Multiplier and Specular, and then replace them with EA's textures. I used GIMP2.6 for making textures. All images are 512 px x 512 px and in png format.
The Mask defines the area(s) which is / are recolorable in Create-A-Style. Red (R, 255; G, 0; B, 0), Green (R, 0; G, 255; B, 0) and Blue (R, 0; G, 0; B, 255) areas correspond to the first, second and third patterns in C-A-S mode, respectively.
Using the UV map for determining the positions of each segments, paint red, green and blue colors over the areas where you want to apply each pattern channels to.
I made the above image as Mask. When applying this mask onto the mesh,
the cup & saucer looks like this.
The Multiplier is a gray scale image. It adds shading on the appearance of patterns.
You can use monotone gray image for this, but the object with monotone multiplier will look 'flat' in game. A good multiplier adds reality on your object.
I suppose many ts3 CC creators use baking in Blender. The multipliers made with baking generally looks great, like professional work. But it has some disadvantages such as limitations on UV-mapping way. And I prefer 'hand-made' multipliers. In some cases, baked textures look a bit artificial. I love the natural- or organic-looking furniture.
I made this image as multiplier for the cup&saucer.
I usually make monotone gray layer (RGB = 141, 141, 141) first, and then add shades over it using dropshadow filter of GIMP. For how to use dropshadow filter, please see this tutorial by MisticRain@BPS.
After this, I add some details such as wrinkles or grungy textures manually if I think it's proper.
The Specular is a gray scale image too. It defines shining or reflective areas of the wall.
An easy way to make specular image is making a copy of your multiplier, and increasing contrast and / or brightness of the image.
I made this image for specular.
Now we're ready to move on next step. Will use TSRWS finally.