How to save position of blocks in cookie/localstorage?

Question

JavaScript

Hello!
Who can paint / give a link to a normal manual (from those that I found - either general concepts, or there is no step-by-step explanation) on how to save the position of blocks after a change in the DOM? Link
to code:
https://jsfiddle.net/waspmax1/m9j7hen3/
Used dragula plugin