first in the map in galforge double click on the planet that you want to specify the forces at to open the template/group editor then click the add in the group editor click add then choose the conditions of the spawning then choose each item you want to add then click the add under the units/buildings list
when you have added all the ships/buildings you want to the planet then close the planet window, and repeat for each planet that you want to do thsis for
harpo