The scenic base goes together really easy, with only the iron halo type piece on one of the banners being something small and fidly to worry about. Guilliman himself also goes together fairly easy, though I had to fudge where the pistol goes on his back. The only pieces that cause any real difficulty are the Ultima (or Agemo if you prefer) symbols that attach to his leather waist straps.
Guilliman has a pair of tabs on his feet that allow him to naturally seat on the display base, allowing him to be interchangeable without fancy magnets or pinning.
I used the tabs on Guilliman's feet to carve out the spaces for him to sit on the base to be used in game.
The base then just got a coat of Stirland Mud for texture, and Abaddon Black around the rim.
When I begin painting a model, I prime black, and then base coat the areas I plan to wash. These areas received base coats of Warplock Bronze for the gold areas, Leadbelcher for the silver areas and Zandri Dust for the tan areas. Then a wash of Argax Earthshade was brushed over those areas and left to dry. Next time, I will work through the layers I use to finish the model.