Normal: a game against another person — the next player who is looking gets seated with you. To play a friend, Invite a friend gives you a code to send them; they press Use a code. The table opens as a shared tabletop with hints off: you two keep the rules, as at a real table. Either of you can turn hints on from the table's toolbox, and the table keeps the rules and shows your plays from there. How a game by hand goes.
Practice: during the alpha only a small number of people can practice against the bot at once, due to small server capacity. Building and saving decks is always open.
Sandbox: a table for one with hints off — both seats are yours, nothing is enforced or automated. Lay out this deck against the bot's deck above, move cards, tap, mark damage and points by hand, roll dice, put down tokens: a tabletop to try lines and teach with.