To activate a Trains seat alert, follow these steps:

1. Log in to your Traveloka account on Traveloka App.
2. Go to Trains.
3. Tap the bell icon at the top right. Then, tap the plus button at the bottom right.
4. Fill in your origin, destination, date of travel, and number of passengers. Then, tap Availability Type and tick Available Seats to get notified when seats are available or just become available again.
5. Open More Options and tick Include nearby stations to get more train options in your city. Then, enter your preferred departure time, seat class, and alert frequency.
6. Tap Set Alert.

Please note that Trains seat alert is only available on Traveloka App version 3.1 and above.