When making a web booking it automatically should appear in the app under "my bookings" but few times this doesn't happen. When this happens it it easy to import your booking to the app, what you need to do is to go to the booking confirmation email that have been sent to you and in the bottom of the email there is a 8-digit code you will need to use in the app.
After obtaining the 8-digit code from your booking confirmation you will go back to the app on your phone and click on the drop-down menu in the top-right corner and select "my bookings". Under my bookings in the middle of the screen there is the text "Import bookings" you need to click, when you have done that you need to enter your social number and the code from the confirmation email and then click import. After this shut down the app and reopen it and the booking will be there.