Warlock – “Expansion” [4th campaign, 2nd mission]

This mission is proving difficult for me – completing it feels like a real punishment: I can’t seem to decipher this nonsensical map. And I don’t understand why I need to run around searching for obelisks when the entire map is available in the menu, and after visiting them, it disappears?
Without the tear, I’m being overwhelmed one after another by strong enemies on this map – where does he get such an army?
Guys, help me complete this mission – explain how to read these kinds of maps...