Board Game Arena

Hello,
After creating the deck, how can I make it visible on the interface?

That's far too broad a question. It depends on what you want each player to actually be able to see - for example cards in players' hands are usually only intended to be visible to them, not to the other players.

Typically you will send the information that the current player can see in the PHP getAllDatas method, and retrieve this data in the JS setup method, where you can then use it to set up the game UI. You can see examples of how to do this in the Hearts tutorial, as well as in more or less any studio project for any game that involves one or more decks of cards.