Hey,

glad I could help you!

Regarding your question: You would normally use a single separate model for all your glass windows, which has several advantages over having just one big house model containing all these elements.

• Separate models only get rendered when they are actually visible in the view frustum
• You can easily assign different materials or shader effects to your models
• Most importantly: You can assign unique actions to every single window plane for special behaviours. This way, you can let them do all the wild things windows usally do, i.e. make them shatter after being hit or let them swing open when the player touches them.

Simple approach, this time without fancy images:

• Model a simple plane or a very flat cube for the glass part and export it, just the way you did with the house. Make sure it's at the center of your scene, so its origin is at zero. This makes placing it a lot easier.
• Import that one it into MED and save it as a separate model. In case you want no special behaviours but just the glassy look, open up the skin settings, check "Effect Setup" and assign an appropriate shader. Are you using the default script templates? Then you would just go with the default material "Glass.fx" which should be located somewhere in your project folder (I hope that's correct; I'm not too familiar with the templates ^^).
• Start up WED or GED (I recommend the latter, even though it tends to crash quite often), open the level with your house model, add several instances of the glass model and fit them all into your window frames.
• Save, build, run - voilà!

And in case you do want a special behaviour later on, create a script action and assign it to your models in WED/GED. This action would normally also include a material/shader effect definition, so you don't have to configure this in MED.

I hope that was comprehensible enough. Please give it a try!