I need to know how to make the colours transparent so i can still see the car layer....

You can turn off individual layers by clicking the eye icon (i think) next to the layer in the layers panel

lower the opacity of the layer also lets you see through the colour, yet see where you are drawing.

Thanks guys, also, how do i rotate an image i pasted into it ?

When you paste something it should automatically paste it onto it's own layer. So just go to the Edit menu, Transform, and Rotate. Other handy transformation options are there also.

Ok. One more thing, where is the button liek in paint where anything in the image is white it will go to background colour ?