From Castle Wiki

Decks are worlds, toys, games, stories, or other pieces of interactive art on Castle. Castle is a network of decks and people who play and create decks.

Navigating Castle to make a deck

Decks are composed of one or more Cards. Once a deck is published, it appears on the creator's profile, and may be shared in the public Castle feed or with a link.

How to make a new Deck

To make a new deck, navigate to the Create tab of the app. Select "New Deck" on the top right corner. You'll be presented with a list of kits. Select any of the kits of start from a blank deck to enter the editor.

If this is your very first time making a deck, welcome to Castle! Please consider reading this guide: How to make your first Castle deck.