Next step, not shown: dry brush the tops and backs of the castings with bright silver. Pay particular attention to the helmets and pilum tips.
After this, things get a bit complicated.
All parts of the figures that will be brightly colored need to be painted white. That’s the shields, crests, and lower back tunic.
Only the outer soldier’s lower back tunics need to be painted at this point. That means the outer two soldiers of every strip of 2, 4, and 8 soldiers, as well as all the command figures. The command figures are all front rank and usually more spaced out a bit due to base sizes, so I always paint them completely, as if they were regular, individual figures. This is why I mount them for painting on their own popsicle stick.
We get slapped around, but we have a good time!