Shooting Game - Need a bit help!

Hello, my game goes about that you have to shoot as much enemys as you can in 30 seconds.

But now i need some help.

I have some problems.

My problems are:

The countdown timer. How can i do that the timer counts from 30 to 0, and after it is at 0, it will go to another frame that will show you the score you got. Oh, i forgot to say, i also don't know how to do that you will get 5 points on every enemy you shoot, but i don't know how to add that at the score text place, and i also don't know how to add that at the end (where it shows your points after the 30 seconds).

I hope you understand me...

Oh, again, and i also don't know how to do that if you shoot the enemy, you will see blood, and AFTER the blood, the enemy will vanish and the new one will come. Yep, i really need loads of help, but they are not really hard question. I have to go after 1-2 hours, so fast help would be VERY fine.