Dig underground tunnels, build rooms and attract creatures at your service, then use your army to annihilate your enemies. Each room has a different use and can attract a specific type of creature, so it's up to you to build the best hive possible. You can even build traps or research new spells to improve your defense capabilities.
Now you can find boosts exploring the map
Does this boost affect all your units or just one?
I would think just the one that picks it up.
This will increase all your creatures level by 1
You can find different type of boosts like bonus minerals/vespene, temporary increase of creatures efficiency, bonus tech points, etc