Gathering Schematics is a big part of Modern Warfare 3's new MWZ mode, letting you permanently unlock Wonder Weapons and consumables to bring into each game with you. Rather than having to find an Aether Tool at the start of a match to upgrade your weapon's rarity, you can bring one with you. Instead of having to purchase a Perk-a-Cola to get your ideal operator perk, you can simply craft one beforehand.
Since weapon rarity and Pack-a-Punch level disappear when you exfil, Schematics are the mode's true progression, letting you push further and faster into the higher threat zones with less prep time each match. These MWZ tips might also help you make some progress, but either way, here's how to find Schematics in Modern Warfare 3 zombies.
How to get MW3 zombies Schematics
To get Schematics for Acquisitions or weapons, you need to either complete activities in MWZ and open Mercenary Loot Caches or Aether Loot Caches, or complete story missions with Schematics labelled as their specific reward. Just like the weapons you find, most Schematics are random and pretty scarce, but you'll know when you get one because they're a yellow rarity item.
The best method that I've found for getting Schematics is to complete Aether Nests and Infested Strongholds you find throughout the Exclusion Zone.
Simply head inside—with a gas mask if possible—and shoot all the yellow cysts to clear it. Be sure to watch for the exploding Nest Crawlers and the Mimics that sometimes disguise themselves as chests. Once clear, you can loot all the Aether Caches inside for a chance to get a Schematic.
Once you've got one, you should exfil out of the MWZ with your Schematic ASAP, since having it in your inventory when you escape will permanently unlock the item for crafting. All you need to do to make your new Acquisition is to click on an empty space in your backpack when prepping your operator, then choose the crafting menu at the bottom. Similar to your Insured Weapon, you can only make new items after a cooldown has ended, so craft wisely.