Perks
Perks are special buffs you can give to either your attacking force, your defensive force (mines, turrets, structure HP), or resource generation. This is unlocked the same time Challenge Mode is unlocked (Command Center level 5). Completing Challenge mode gives you Perk coins. Collecting a number of these will allow you to craft a variant of the available perks (also depending on the quality of the perk coin).
Overdrive (Red) is used for offensive purposes for when you attack other bases
Stronghold (Blue) is used for defensive purposes for your structures and base defenses.
Micro Management (Green) is used for the functionality of the base like resource generation and unit training.
There are also four slots to be used for free and the remaining two slots are unlocked by spending Celerium or Medals.
You can have any combination of perks but only four can be active. You can't craft a new one without selling one of your current ones so choose wisely.