Clear up some confusion for a 40K player

So as a 40K player I bought Skaventide and tried out spearhead - was a heck of a lot of fun, but try as I might, there is a few things I couldn't get from the rulebook, or not sure if I'm understanding it correctly , and skipping through a combat report video didn't entirely help.

• When deploying armies , does your entire "territory" count as your deployment zone? Can I really deploy on the centre objective? What prevents armies from just both deploying in the middle and starting to fight immediatly? (I saw most maps divide the board in 2, some of them have no man's land)

• For abilities that state "In your territory" is this the area you started the game with, irrespective of who currently holds those objectives? In my game I brought in reinforcements in my territory , right next to the objective my oponent held (My home objective), outside of combat?

• When bringing in reinforcements, can they still move? On the ability it doesn't state that you can no longer move.

• Am I correct in that fighting alternate? So even if I charged with 3 units, and 1 was in active combat, since I have priority, I get to chose one of the engagements, then my oponent gets to chose one, even if he was charged? Following that, lets say I choose Group A to fight, and He chose Group B, do I then also have to chose Group B to retaliate later? Or does a "Fight" Counts as both sides fighting? So if I chose group A, I fight, he fight, then he chose another group?

• When in combat with a unit, if only half the unit is within 3 inches of my unit, can I only hurt half of them, and can only half of them fight me?

• Wounds always spill right? So all damage goes to the damage pool, and then gets distributed, it's not like 40K where if an attack does 3 damage, but I only have 1 health, the other 2 damage dissapears?

Thank you in advance!