Cdonovan - Welcome to the forum! I'm sure you'll find it to be very friendly and helpful.
Regarding your Ju88, which group's markings are you intending to use? There are many reference sources on the web, and maybe we can help you locate some.
Here's a pic describing exactly what Pix was saying.
Pix was an enormous help to me, and if not for him, I wouldn't have repainted the original camo in the decal areas. After the decals were applied I blended the white back in a little closer. I think it looks much more realistic this way, but as others have said, these aircraft were painted in many different methods and environments, so check out all the references you can. All of the profile layouts that I had showed the markings as applied after the white.This is the same model as in my sig pic (below), which can be enlarged by clicking on it.
Pix has has posted shots of his methods also in the past.
I don't have the link right at hand. If I find it I'll post it, or maybe Pix will provide it for you.
Be sure to post some pics of your progress. There are quite a few Luftwaffe fans here.
stinger