Maybe you see some maps with same but different textures looks like this:

• You need a new .txt file named after map like this: css_dust2_detail.txt
• You need to know every texture name for add in txt file.
• You need to change actual texture with new one

prdwillb is original name texture,
detail/concreteground.tga is the new texture file located in gfx/detail (without .tga in txt file)
2.1 is the height scale of the texture
2.1 second is the width scale of the texture

If you create a texture like original one you can use 1.0 scale for both height and width
Or change values and test in game how it looks
256x256 dimenssions for texture is a good size