I want to know how to provide the numbering for each tab, so that author can provide the number to the tab as per their requirement/preference/relevance.Requirement
As per the screenshot the number of tabs are fixed, so you can have another tab - order selector - where you can configure the order.
Btw, I would prefer this to be done as a container and subcomponent structure instead of a blobbed up dialog.
Have you looked into using the "sling:orderBefore (String)" proeprty and update it dynamically using Sling Models?
Contains the name of the sibling node that the current node should be positioned in front of."
More details at