When you have booked a video call through Ahum, a confirmation will be sent to you via email. Follow the link in the email to log in to Ahum, or go directly to Ahum.se and log in with Bank ID. Then go to the menu at the top left and select My Bookings. Click the Join video session-button next to your booking.
The button becomes active, and you can enter the video call about 15 minutes before the booked time.