Leaderboard Shareable

Hi everyone
I’m interested in all aspects of video games. so i need to know what my team is talking about, I’m looking for a way to learn how to send the “leaderboard” everywhere on the web {Siteweb, Facebook, Steam…//Refresh Autonome}, on Unreal we have good information recovery players and stats {XP’s/Rank} remain shared.
In the idea that I am, I would like to share this on the network, whether it is facebook or my website or elsewhere, it seems to me that this is happening in .json, and on XML.
Could you explain to me how to do these, in a simple way to start, with the theory, I could deepen myself the subject… I only need the basics.
[Own XP = 35/40h of c++ code, but years as tech art]
A big thank-you,
see you soon.