Computer does not recognize file

[oaphish 0]

 So i'm sure there is some very obvious and simple answer to this, but I'm asking nonetheless. 

First of all I'm running SC4D I downloaded the NAM, and I'm using windows.

I tried downloading one of the buildings, specifically the ultracollider.

My computer does not recognize the file.

Am I just supposed to drag it in to SC4 plugins folder?

Is there another file I need to download before doing all this?

Thanks tons for your help

[CaptCity 4,942]

When you download an item, it is in a zip folder. You can unzip it to obtain a regular folder or the files can be dragged out of it.. The regular folder or the files can then be placed into the Plugins folder. If you are trying to open the files within the regular folder (.dat, .sc4lot, .desc), that is not necessary. They are the files that are read into the game.