No problem, I'm starting a new game with a random team. Normally I'd customize a team for a more tailored experience, and break vulnerabilities selectively for the same reason, but for this example, I'll go with a random squad and show the first 13 days in an otherwise typical game for me.
Day 1: We start with a red-text Chosen, which tells us a Minor Vulnerability - Morality. The text is based on whether the Chosen has Core (blue), Significant (green) or minor (red) morality. I still don't know what her Core vulnerabiity might be, but at least I know not to use Threaten on her. I try Slime and it does mediocre damage, so Innocence has got to be a Significant Vulnerability to her. I try Attack and it does a much better 70 damage. The text also indicates she doesn't mind being hit. The rest of the fight is nothing but spamming Attack so we can get her well over 200+ trauma so we can start getting EE out of her Tier-1 downtime actions. Our first EE goes to Psychic Reading.
Day 2: Psychic reading confirms my earlier assumptions - Minor Morality, Core Confidence. Also Core Dignity, though we can see she's slightly less vulnerable to it, so we stick to spamming Attack the entire fight. It won't help with getting extra EE yet, but the unresolved trauma will increase Angst and, by extension, our damage multiplier on her. You can already see the difference, we're already doing more damage now. After the fight, we pick up Wide Deployment.
Day 3: Same as before, spamming Attack. Oh look, a wild blue-text Chosen appears. I don't need Psychic Reading to know she's weak against Threaten, but let's use it anyway. As it turns out, she's just as vulnerable to Slime and Shame. The rest of the fight is just me spamming Threaten on her, to get her generating EE for us like her less scrupulous new ally. Unfortunately the fight ends on Round 7, and there just wasn't enough time to get 200 EE. We pick up Fast Breeders and start the next day, targeting the new Chosen.
Day 4: Not much to say, Prophet gets Threatened a lot and of course, she stats making that sweet EE for us. We pick up Enhanced Polymorphism.
Day 5: Prophet remains the target for now. Nothing special happens, just a lot of Threatening. Then we get Coordinated Deployment.
Day 6: Same as before, yawn. By now, Prophet has the same damage multiplier as Calamity. We pick up Focus, not Weakness Sense, as I can't be bothered to use Surround until I have some basics in place.
Day 7: Back to Calamity with Attacks. We get Eager Breeders afterwards. Expecting the third Chosen any day now, it can vary a bit.
Day 8: Back to Prophet with Threaten. Ah, there we go, green-text girl is here. From what we already know of the other two, we've already deduced she's going to have Core Innocence (since neither of the others has it) and indeed, there it is, along with the accompanying weakness to Slime. We manage to get DISG over 200, so she'll be earning EE right away. I expect to spend the next 3 days farming 3 EE each in order to get a basic commander in place. Might as well also spam Slime on our new opponent to get her damage multiplier up. In fact, that's all we'll do until day 12. I'm sure there's room to get fancier here, but my intent is just to show what can be done in a few days with a basic 1x4 or 2x4 commander.
On reaching day 12, I've got 13 EE saved up and the Chosen all have roughly the same damage multiplier. For future reference, I've also noticed Prophet has pre-broken Innocence, which explains her starting weakness to Slime. Now it's time to buy a commander and go to town. I pick up Weakness Sense, Perception and Cunning. We'll just be using a 1x4 (1 capture, 4 round duration) commander today, as there's not quite enough EE to pick up a second capture just yet. Looking at our Chosen, it's clear that Jackal should be our first target - she's weak to INJU, plus she's she's the easiest one to strip (weak to EXPO), which means she's going to be our first target in any combat for the foreseeable future.