1. 1 infantry platoon is 1 troop choice? Meaning i would need 40 men minimum?
An Infantry Platoon consists of a Platoon Command Squad, and anywhere between 2 and 5 10-man Infantry Squads, together that makes one troops choice at a minimum of 25 men.
2.Advisors, do they attach to: command squad and everything else in your command platoon?
I'm not sure what you mean, if you buy a Commissar, he attaches to the Command Squad itself.
3. Then they go to infantry squads, iron fist squads and strom trooper squads in that order? or can i choose which?
They go: Command Platoon, Infanty Platoon Command Squads, anywhere you like.
Unless you take the Independant Commissars doctrine, but that's another story.
4. I want to make an infantry heavy army (lotsa men), how many men should i use in a 1000pts game?
As many as possible, obviously.
5. Can you help?
I think I just did, or did you mean about a list?
6. Should i swap my demonhunters codex for a guard one?
Yes, join us!