Schematics are the recipe you need to create new fusions in the game. Every fusion has a specific Schematic you will need to gain to unlock and fuse it.
Where can I find Schematic X?
The best place to look for a specific schematic is to go to the areas where the familiars needed for the recipe live. For example, to make Bor'lan you will need 1 Mer'land and 1 Bob. These familiars live in Bit Valley so to acquire a Bor'lan schematic, you will need to search there.
What are Schematic Items?
Schematic Items are a consumable item in the game that will create a random schematic that you do not already have. So using an Epic Schematic will create a new epic Schematic you don't already have. However, these items can only give you some of the schematics in the game.
Which Schematics can a Schematic Item give?
There are two kinds of schematics in the game: Regular Schematics and Invasion/World Boss Schematics
Regular Schematics are found on Zone Dungeons or Raids. These schematics can also be obtained using a Schematic Item.
Invasion/World Boss Schematics are found in, well, Invasion and World Boss areas of the game! But unlike regular schematics, you cannot use a Schematic Item to obtain them.