Hi Nishank, I have attached with this comment two posts which contains all the details about exploring finland and places you must visit. You can go through these and plan your trip.
Hi Nishank,
The best places to see the Aurora Borealis are in areas free of "light pollution," which Oulu has plenty of. The Lapland Hotel and the Hupisaaret Islands City Park are two popular auroral viewing locations.
https://travellifo.com/14-best-attractions-of-oulu-finland/
Oulu's aurora season lasts from late September to mid-April. The rest of the year, Oulu is too bright to see the Northern Lights. The Northern Lights, on the other hand, are never predictable. The best way to explore the exhibits is with a knowledgeable tour guide who is familiar with the top photographers.