Review a receipt and book it

Open Inbox. The queue on the left lists the documents waiting for you. Click one to see its fields.
Check Supplier, Date, Amount, VAT rate and the note. The app has read them from the document, so correct anything that is wrong.
Choose a value in Account / category. It must have an SKR03 account (a number from the standard German chart of accounts), otherwise the booking could not be posted later and the app asks you to pick another one.
Click Review + next. This saves your changes, marks the booking as reviewed and moves on to the next document. Skip leaves the document in the queue.
A document with a shield symbol has an open blocker, a conflict the app found. Review + next stays disabled until you have dealt with the notice shown above the form.
Reviewed is not final yet. Open Bookings, open the booking and click Post booking, then confirm with Post it for good (unchangeable afterwards).
After posting, the booking can no longer be edited. A mistake is corrected with a reversal booking, see Reverse a booking.