You can organize your cards any way that makes sense to youby set, Pokmon number, rarity, or type
For example, let's say you have Seraph of the Suns and two 2/2s on the ground
Finally, Y'shtola, Night's Blessed represents the MMO
Note that you must choose the target creature before revealing the hand, so while you can exile from the hand if it's dangerous, you cannot see the result and then decide to exile a different, more threatening creature instead
Other times its a strategy - for example, knowing you want to play as many lands as possible or win using an alternate win method, such as milling your opponent so that they lose when they cant draw any cards
You are limited to redeeming only 10 codes at once, and you can either copy and paste the typed-out codes, type them out yourself, or scan them via your camera