HElp With game!

My game is gonna be all about defending your house from waves of zombies, but i need some help 
1. How do i manually adjust how many zombies will be spawned in one round?
And how do i make enemies that are harder to beat show up later in the game?
2. How do i make the game detect the last zombie so the "buy menu" can show up?
3. The only thing(epxt you and ur gun) that keeps the zombies away from the house is a fence, how do i adjust so ecach type of zombie has to hit the fence this or that many times before it breaks?
Alot of questions here, i know i should make something that is more suitable for a beginner but i just fell in love with this idea :P
Thnx from sweden, and excuse my english XD

1. How do i manually adjust how many zombies will be spawned in one round?
And how do i make enemies that are harder to beat show up later in the game?
2. How do i make the game detect the last zombie so the "buy menu" can show up?
3. The only thing(epxt you and ur gun) that keeps the zombies away from the house is a fence, how do i adjust so ecach type of zombie has to hit the fence this or that many times before it breaks?
Alot of questions here, i know i should make something that is more suitable for a beginner but i just fell in love with this idea :P
Thnx from sweden, and excuse my english XD
Comments
http://www.youtube.com/user/GameSaladCookbook
And welcome to the forums!
but seriously, watch them over and over and over and you'll eventually get.
sounds interesting, keep us posted!
-Jobo
http://gamesalad.com/forums/topic.php?id=11558
Essentially, when a variable reaches a certain number, it will 'trigger' an event.
For example:
"2. How do i make the game detect the last zombie so the "buy menu" can show up?"
One way would be to have a count variable - an integer - that would count down every time you kill a zombie.
Let's call it 'ZombieHorde'
And let's have a variable for the Zombie's health - it'll be made on the actual Zombie Actor (so a 'self' variable' ) and we'll call it ZombieHealth and make it 5 for now.
In your Zombie Actor, you'd have a rule that basically said:
If collides or overlaps with player bullet
Change variable ZombieHealth to ZombieHealth -1
Then have the rule:
If ZombieHealth is less than or equal to 0
Change ZombieHorde to ZombieHorde-1
destroy zombie
Then in a controller actor (just an invisible actor to check on stuff) have the rule:
If ZombieHorde is less than or equal to 0
do the stuff that shows the buy screen.
The nice thing is, at the start of each wave, or at the start of each scene you can change the ZombieHorde variable so that it gets progressively harder.
Wave one you'd set it to 5 for example. when you kill five zombies, next wave starts.
When the next wave starts, you'd set the ZombieHorde variable to 10, for example.
Also, having the Zombie's health on the zombie actor means you can change that for different actors, but the code remains the same.
But yeah, go look at the videos too!
Hope that helps!
QS