Professor Hastings will then send you out to practice your skills. Your first task is to capture a Minun/Plusle (the one you didn't choose as your partner) and use its Field Move. Exit the Ranger Union and head east towards the Ringtown Forest.
Inside the forest, you'll quickly encounter a wild Minun or Plusle. Initiate a capture by tapping the 'Capture' icon. Remember to draw circles around it without lifting your stylus or letting it break your line. Once captured, you'll be prompted to use its 'Electric' Field Move on a nearby obstacle, likely a small electrical panel or a group of Starly. This teaches you how to utilize captured Pokémon's abilities to progress. After successfully using the Field Move, return to Professor Hastings to complete the mission.