Making an entity

[MrDosht]

This is probably a stupid question but how do I actually use the material editor to make a .mat file? When I try to open the file it only lets me open .mat files D:

Well the material editor is the easy part!
You are going to need photoshop or gimp(Unless you find somewhere ready-to-use textures)
Make your texture and then save it as jpg,png,dds,tga and put it into the billboard folder
In the material editor:
Firstly you change The type to: SolidDiffuse
The go to Textures and click the Diffuse
A new option shall appear
Just press the square button ([...]) below the diffuse File
Load the file from the billboards folder
Change the Blend mode to Alpha(Not sure try Add if alpha wont work)
Press File->Save as->Choose location(Inside the billboard folder )
Save the mat file with the same name with the picture file
That's it!!!
Here is some pics on how to do it:
http://www.mediafire.com/download.php?72e8cqbtacfwpc8

Thanks! I managed to make a .mat file with that but I can't seem to open the file from the modeleditor, it doesn't appear in the billboards folder even though that is where I saved it... should I rename it as a .ent file?