Castles
A castle covers 3 × 3 squares and lands centered on the square you click. Type a name first if you want one on it. It only goes on green: never the corrupted zone, never a tower, never overlapping another castle. Click a placed castle to take it off.
Towers
A tower bites 1 × 2 squares out of each corner of the zone, which is why the outline is stepped rather than straight. Towers can be attacked, so click one to mark who holds it.
Royal City
The Lv 7 Royal City sits dead center, the same distance from every edge of the zone. It is what everyone is fighting over, so click it to mark who holds it.
Colors
Nothing has to be named before you can start. Pick a color and go. Naming one is how you say which union it stands for, and named colors appear in the key under the board.
Pencil and shapes
The pencil, lines, arrows, boxes and circles ignore the grid completely, which is what you want for rally lanes and staging rings. Rub out removes one stroke at a time, and undo takes back the last one.