The first thing to know is that a character's Deck can hold 6 different cards at the same time Lost Ark Gold. Thus, you can swap cards at any time. The cards that make up the game come in sets. If you're making a deck with a lot of cards, the greater number you have within the same pack the more bonuses and buffs you'll earn from these cards.
This means that using random cards from different sets is significantly less efficient than equipping cards from the same set.
That said, this doesn't mean that all six cards have to be of the same set. It's possible to choose as little as two as well than six of the exact same card set. The type of cards you be using completely will depend on what kind of effects and bonuses you'd like for your character.
If you are putting cards into your deck, make sure you click"Set Effect Details" above the card set "Set Results Details" option in the upper right hand corner of the set of cards to see any bonuses that the set can offer you Cheapest Lost Ark Gold. This will assist you in choosing what Card Sets you want to put in your deck.