Board Game Arena

I am making a card game. I want to show how many cards each player has in their hand in the player list on the right hand side. I have seen people put custom data in this area. Where is there documentation on how to do this?

From the wiki page related to <game>.js : http://en.doc.boardgamearena.com/Game_i ... amename.js
There is a section related to 'Adding stuff to player's panel' that should answer your need.

Thank you.