Create categories and add accounts

Open Settings, then Categories. A category is a label such as a type of expense; the AI uses it to sort documents, and each category points to an account of the chart of accounts (the numbered list of accounts used for bookkeeping).
Choose New category and fill Code and Name. The code cannot be changed later because bookings refer to it.
Fill SKR03 account with the account number the category is booked to (SKR03 and SKR04 are the two standard German charts of accounts); SKR04 account is optional. Without an SKR03 account the bookings cannot be posted and the DATEV export refuses them.
Optionally set Direction (expense or income), Default VAT rate, Colour and AI hint, a sentence that tells the AI when to choose this category. Then choose Save.
To remove a category, open it and choose Delete or archive. An unused category is deleted; one that bookings already use is archived and hidden.
For the accounts themselves open Settings, then Chart of accounts. If the list is empty, the page offers to seed the chart so you can start booking.
To add an account the chart lacks, fill Account (four digits), Name and Type, then choose Add account.
If the account list shows the notice Chart SKR04 not confirmed, the account numbers of that chart have not been checked by the tax adviser yet. Until they are released, accounts, reports and the DATEV export are not binding.