return float4(finalcolor.rgb,1.0);
The 1.0 is the alpha value. You can write 0.5 instead and you'll get a semi-transparent model. Alternatively you can write "texCol.a" which will take the alpha value from the diffuse texture.
float3 tNorm = tex2D(ReliefSampler,IN.UV).xyz - float3(0.5,0.5,0.5);
float4 texCol = tex2D(ColorSampler,IN.UV);
This is where the texture lookups happen, one for the diffuse texture, one for the normal map (The normal map is the one on top). You can do a simple uv shift by adding the following line in front of the two above:
