How to use plugin

Hey I am new to this plugin. I am trying to figure out how I add custom items from the plugin Item Perks: Legendary Items, in the custom loot tables on this plugin. I keep reading you need an API from the developer to add that plugin to Loot table. How do I add a API to the Loot Table plugin?  Also with the other plugins I am using Heli Signals & Bradley Drops, how do I add their APIs for those plugins to the Loot Table to customize each heli/tank difficulty loot tables. I see the option Plugins on the loot table main menu, I just don't know how to add those plugins, to edit loot items to customize there loot tables. I see in the data>Loottable2>plugins file of Loot Table on my server, do I just drag a json file/cs file to that folder to add API for those plugins? Any help would be awesome, I am learning as I go.

These are the plugins I am trying to add to this plugin to customize the loot tables.

Idk if others have found how to do it correctly.

You should ask the developer of these plugins to implement these APIs in their plugin. Once they implemented the api, the plugins will automatically show up in the Loottable UI.

There is nothing you can do there unless you have some coding experience.