Well, you'll either need to collect the cards from Arena booster packs for the sets they came in, or else directly 'craft' the specific cards you need using MTG Arena Wildcards - effectively tokens you can exchange for the exact Common, Uncommon, Rare, or Mythic Rare card you want, depending on the type of Wildcard
PREPARE FOR A SPECIAL DELIVERYJovial troubadour Zinnia delivers the pain, plus a whole litter of offspring to overwhelm your opponents
CC - Pound (20) Retreat: C Weakness: F Resistance: P ------------------------------------------------------------------------------ Wigglytuff A34 - Rare Type: Colorless Evolution: Stage 1 Evolution (Evolves from Jigglypuff) Level: 36 HP: 80 C - Lullaby Effect: The Defending Pokemon is now Asleep
However, the great nation abruptly falls silent and closes its borders
I encourage you to go check it out because, frankly, I'm about to spoil it a bit