How to create a texture for the window?

How to create a texture for the window?

Hi Samuel.
I create a windows using the texture to show glass and window frame. Now I am trying to understand how to make the texture to be transparent and reflective same time for the glass part. To make the transparent glass I change (in photoshop) opacity amount to 50%. So, I expect that glass will be 50% transparent. If I am going to use the same texture for the reflections, what I need to do? I have followed webinar tutorial, but there is example for non-transparent textures. I think, I miss the logic how to make a proper reflections and refraction on photoshop. I also tried to see example project. There, for the windows you use only one texture for the diffuse and opacity slot, but I don't have a photoshop file for the texture to see how it was made. When I open preview it seems like all glass totally transparent, but max preview shows coloured glass.
Please see attached photoshop file.