yep, you do everything back to front compared to 'normal' painting.
I draw the design on the outside (the protective film) first with a permenant marker pen. then mask the inside and use a craft knife to cut the design into the masking tape/film.
Make sure you wash the shell first with hot soapy water. and dry it fully.
As col said try and paint the darkest colours first.
the main thing is, Keep it simple to start with. get a feel for the airbrush and what you can do. then you can move on to more adventurous things.
don't try to run before you can walk.
I've been doing this for 13 yrs or so, and I'm STILL learning stuff!
