I purchased the Dark Imperium set a few weeks back but have been doing so much research on how to start painting and find so many conflicting comments.

I have all the base paints, layers, shades and dry paints and also a chaos black and mechanicus standard grey to paint all my models. I have all the tools and setup is ready to go. I'm unsure if I need to spray them first or if I can just apply the base paint macragge blue.

The guy at GW told me to apply the space marines with the chaos black and then macragge blue for the base coat and visa versa with the death guard.

Any help would be greatly appreciated. PS I painted a bunch about 15 years ago but don't remember a thing!