The redemption is super easy, just download the official app and register your pass in the app and you are ready to go. The mobile pass also comes with 5-day unlimited data eSIM, the connection is only 4G but fast and stable!
Most importantly is the app will show you the pass validity, your visitation history, and even let you save the attractions you would like to visit.
Attractions wise are still good, where you can visit quite a number of places if you plan your time well. For 48 hours pass, we managed to visit:-
1. Hanbok rental outside Gyeongbokgung
2. Gyeongbokgung (free entrance if you wear Hanbok)
3. N Seoul Tower
4. Lotte World Adventure
5. Sea Life @ COEX
6. E-Land Cruise
7. Nami Island
For better transit, get the Climate Card and loaded with 3-5 days pass to pair with Discover Seoul Pass, it helps to save more money and time.