Diffuse, Specular & Normal Maps

dds plugin for photoshop can be downloaded from here:
http://developer.nvidia.com/object/photoshop_dds_plugins.html

alternatively you can save your textures as tif from photoshop (make sure the image size is 512x512 or 1024x1024). save them into your objects folder.

once you've exported your object into sandbox, open the material browser and select the objects material by using the eyedropper [see below]. you can change the texture file by clicking on the folder next to the channels.

The diffuse channel is the standard texture file which represents colour. By expanding the + box next to diffuse you will have options for tiling of the texture. This tiling will be reflected throughout all of the other channels.

Diffuse Map:

The specular channel defines shine. Use either gray scale images where white is shiny, black is dull and gray is anything inbetween. Change the specular colour (default black) to a light grey. Then adjust Specular Level and Glossiness to suit the material.

Specular Map:

Normal mapping is a technique used for faking the lighting of bumps and dents. Normal maps can be created in photoshop either using the nvidia dds plugin (file/save as/*.dds) or by downloading xNormal and using the photoshop filter.

Normal Map:

Complete Material: