Modulus Core is a mod that adds two new blocks: The Modular Assembler and The Modular Disassembler. These are used to work with modular items, or items with several interchangeable parts.

The Modular Assembler

The Modular Assembler is used to make modular items from components. It has four input slots for components, and one output slot for modular items. Be wary, components will likely have a specific input slot designated to them.

The Modular Disassembler

The Modular Disassembler allows you to retrieve the components of modular items, allowing for interchanging them to make it so you don't have to make the same components twice.

How to use Modulus Core

Modular Core is not meant to be used alone. In fact, you can't really do anything with it unless it's being played with a mod dependent on it. 

Assembling modular components using the Modular Assembler isn't a recipe. So, each input slot must be checked with a tag for that specific component type (For example, any bed frame, or any fishing line). Then, the modular item should store data based on what components are involved, which affects their textures, stats, and functionality.

For the Disassembler, you'll need to use the data stored within the item to determine what components should be outputted.