How do I make a "Datablock"?

[Captain Crazy]

I have downloaded Chrono's mod for changing the amount of item slots and it says I need to make a datablock for something. So...

What's a datablock?

[Ad Bot]

[SuperToxic]

A datablock defines characters, objects, weapons, and vehicles.

Quite complicated actually 

[John1701]

In layman's terms it is imposable to understand.