Create a new client

In the sidebar open Clients and choose New client.
Type the legal name of the company in Company name (legal). The app fills in Short name from it; you can change it. The short name appears in the page address.
Choose the Country: Germany or Switzerland. The country decides which tax number the form asks for, such as VAT ID.
Enter the tax number if you have it. The field is marked as optional.
Choose Create client. The new client appears in the list and you can open it to upload documents and prepare bookings.
If the default setup (chart of accounts, VAT rates, categories) could not be created, a yellow notice has no default setup appears right after you create the client, until you leave the page. Without it no invoice can be finalized. Seed defaults again tries again; the button is shown only to people who may create accounts, and not when the notice says the chart of accounts has no default setup yet (that one cannot be created automatically).
Choose the Chart of accounts. A German company starts on SKR03; SKR04 is offered only when it has been switched on for your firm. The SKR04 account numbers have not been checked by the tax adviser yet, and the form says so. The chart cannot be changed after the first posting.
A company founded part-way through the year, or one that changes its closing date, has a short financial year. Open the client, then Settings and Periods, and in Short financial years enter the First day and Last day, choose the Reason (Founding or Change of closing date) and choose Add short year. A year can be at most twelve months, cannot overlap another year, and cannot be added over a month that is already closed. A changed closing date needs the tax office's consent: note it in Tax office consent (note). Without a short year every year follows the start date of the company.