You stand still outside for 1–2 hours and temperatures can drop below −10°C, so wind chill is the real enemy. Dress in warm layers, windproof outer shell, hat, gloves, and insulated boots — see what to wear for the Northern Lights.
For a camera, shoot manual: aperture as wide as possible (~f/2.8), ISO 1600–3200, shutter 5–15 seconds (shorter when the aurora is moving), manual focus at infinity, on a tripod, in RAW. For a phone, use Night mode 10–30 seconds on a tripod or steady surface, the rear 1× lens, flash off, and the timer to avoid shake. Full walkthrough: Northern Lights photography settings.