Can I enter a passage manually in the app afterwards?

If you have a GPX track from your chart plotter, you can import it (see below) — that’s by far the most convenient option. If you have to copy things over from memory or from a paper logbook, that works too, but the result may not be quite what you expect. The app calculates all your statistics from the many individual entries: the more there are, the more accurate the result. You probably won’t be able to transfer enough entries from paper to reach that accuracy.

If you still want to do it, this is the easiest way: create an entry and adjust everything (time, date, position, weather and so on). Then duplicate the entry (inside the entry, under “Database”, right at the bottom) and change the values that differ — at least the time and position, most likely. Repeat as often as you need.

First create a new, empty logbook — the GPX file will be imported into it. Even if you want to add the data to an existing logbook, import into an empty one first and, once you’re happy with the result, move the entries where you want them. With the empty logbook in place, on an iPhone or iPad simply open the GPX file with the Logbook app (from an email or the iOS Files app, for example). On Android, go to the Tools tab → Import GPX file.