At the start of every mission, you are provided with all the necessary intelligence to plan out your tactics. Simply go into the tactic view to access all the information you need.
Let's take a look at one of these structures as an example.
One thing to pay attention is that this structure will slowly construct guardians to hunt you, very powerful but slow combatants that will relentlessly pursue you. One way to deal with it is to kill it before it produces enough guardian to overwhelm you. However, this structure has many other attributes that heavily fortifies it.
Not only does it gain range when you attack it, it also can unleash devastating area attacks that will destroy you if you are not careful. Even if you managed to take it down, a powerful wave of enemies will retaliate against you.
A bit unfair?
Well there are many way to neutralize or alleviate the threat. Commanders preferring hit and run strategies will find these guardians move very very slow, so if you move fast and plan your path you can get away not having to fight a single one of these.
Defensive oriented commanders can deal with these threat by a few well placed command relay and a turret formation, wise use of teleportation allow commanders to stay in the comfort of their heavy defenses most of the time. Assault oriented commanders will carve a path straight to these structures and face the problem head on after mastering an army. I will leave some of the more devious methods for you to discover.