I will answer your Dummy question for now. That is not much of a noobish question though. If you are not familiar with trigger enhanced spells then maybe you don't know so someone like me will tell you
.
Dummy's are units that are used in trigger enhanced spells. Trigger enhanced spells (if you don't know) are just spells but made more complex and entertaining by triggers. Dummy units are needed in these to do certain tasks within the spell. This might all sound confusing so I will give you an example.
Take the spell Blizzard. It is a AoE spell that slows enemies. Now what if you wanted the enemy to also be stunned as well? In the object editor, you cannot stun an enemy within the Blizzard ability. Here's where triggers come in.
As I said, trigger enhanced spells are more entertaining. Isn't it entertaining to see a bunch of Footmen stunned underneath a Blizzard as they take on the next wave?
Now the within the triggers you will need the assistance of Dummies. You can have them created when your Hero casts Blizzard. Then while Blizzard is in effect, give the Dummies an ability that stuns (such as Storm Bolt but without a projectile art and no damage) and order the Dummies to stun each target in the AoE of the Blizzard. After the Blizzard is over, remove the Dummies from the game. Altogether it looks like the Blizzard was the one that stunned the Footmen!
Just in case you don't know, Dummies are invulnerable, invisible, and unselectable, so they are completely undetecable in the game. You can give Dummies these attriblutes by giving them the Locust ablility and changing their Art - Model to just nothing. That will make it invisible in the game.
Good luck with your spells!