This is a simple tutorial on how to create a .VMT file for your .VTF. Your VTF should have already been created using a program such as VTFTool or Nem's Photoshop Plug-in (highly recommended.)

A .VMT is a simple text file that tells the engine where your texture/spray is. It should look similar to this:

"LightMappedGeneric"
{
	"$baseTexture" "VGUI\logos\your-spray-name"
}

Save this as "your-spray-name.vmt" and place it in the materials\VGUI\logos folder of your chosen mod, along with your .VTF of the same name.