Sorry should have specified that with the app you can directly set the arrival time and exit and fill in the rest later. On the website you have to complete all info prior to setting the arrival time.
I use the app to do most of the checkin as it can scan your passport. I skip the photo as I have a stock photo I use for all sailings which can be uploaded, but only on the website. So I fill in everything that's easy to do on the app, then go to the web to do the rest.