Why do a dark wash BEFORE the base coat you ask? Because the shadows might show through the thin layers of the base coat, giving the miniature more indepth shadows – or because I’m crazy.
Make sure you’ve given the Primer time to be fully dry, per the instructions
Create a super thin wash, with quite a bit of water and a little black paint.
Apply the wash generously, it will flow off the mini.
Let the wash dry. It takes a while, since it’s mostly water.
Admire the nice shadows and textures that weren’t visible before.