How do I make my own armor trim and an item that can be used as material in smithing table (read body for more info)

Basically I want to do my own armor trim and to make new item that can be used for unique color for trimming armor (like how some mods like Create make custom materials that you can use for your trims) and a set of armor on which one you can apply any armor trim.

The problem is: I do not know how to. Asking you to help me!