Hi Rlaney,
welcome to the forum.
Sorry I can't be very specific at this time (it's getting kind of late here and I have to go to bed), but check out the Orks, Aquilaeian, and Space Vikings for troop invasions.
Also
this thread might help.
I'll post a more detailed answer tomorrow or at the weekend. (if somebody doesn't beat me to it
).
Rollo