601.1. Depending on the card type, to use a card is to summon a creature, to cast a spell, to cross a gross gear, to fortify a castle, or to expand a field. Using a card affects the game.
601.1a A player declares to use a card, including changing conditions. The card leaves the zone it is currently in (usually the player's hand) and is moved to the anywhere zone. If a player is prohibited from using a card, that player cannot declare to use that card. Also, pay for alternative costs even if you do not declare it.
601.1b If a player uses a card from their mana zone, the card is moved to the anywhere zone after the payment of its mana cost is completed.
601.1c When paying the cost of a card, the civilizations of that card are paid first.
601.1d The player determines the total cost of the card. Some effects may increase or reduce the cost to pay.
601.1e The player pays the total cost.
601.1f After the mana cost of a card is paid, that card is used immediately. If the card is modal, the player announces the mode choice. Trigger abilities that trigger due using the card trigger.
601.1g The player specifies what to pick when the card instructs to choose something. If the ability is instructed to select more than one at the same time, you can not choose the same thing more than once. If the ability is instructed to choose "by every", or the same ability exerts multiple effects, a player can select the same thing more than once if you do.