Well I tried the FAQ and I couldnt find anyone with the same problems as me. Here we go:
When I put my DDS file into the correct folder and stuff, and I want to select my image in the MT, it just doesn't show anything OR it shows me a red square, what can I do about it?

^up

The red square means your DDS is erroneous. DDS files need to have a size dimention equal to a muliple of 2 (Such as 512x512, 1024x128, 128x256, etc). Try fixing that.

Working! but how do I make the white background disappear? (the images background)

You need to save your DDS in DXT3 mode (explicit transparency). Remember that white doesn't equal transparent, so you'll have to set your transparency or alpha layer in photoshop.

Thanks alot! I think I got enough information to make a nice looking track now