The start could also be from the perspective of the Krypton OC. They could be on Krypton, in the middle of some sort of upheaval. A scientist or a wise elder sends them to Earth for safety. When they arrive, they are immediately overwhelmed by the new environment. Barry Allen, sensing something is off in the city, zooms in and finds the OC. Their first encounter is filled with confusion, but also a sense of potential for an interesting story.
It could start with Barry Allen noticing a strange energy signature in Central City. When he investigates, he finds the Krypton OC. The OC might be disoriented, having just arrived on Earth. Barry, being the hero he is, tries to help the OC understand where they are and what has happened.