You can have up to 4 copies of each card, and its generally best to go ahead and include the maximum number of copies of each card to increase your chances of drawing the cards you want and to focus your deck on a specific play style or goal
I'm going straight to produce a competitive Merlin/Mim deck as my first Rise of the Floodborn deck
You can then turn around and continue to challenge your opponent's characters
When you challenge an opponent character, you compare your character's Strength to your opponent's character's Willpower and if your Strength is equal to or higher than the opposing Willpower, you then banish that opposing character
Each starter deck comes with the 60 cards needed to play, two of which are foil cards, a booster pack, and newly colored, in the scheme of Rise of the Floodborn , damage counters, Lore tracker tokens, and a paper playmat