You will receive benefits backdated to the 1st of the month in which you made your application, provided that you already had a right to benefits at this time.
Following approval, payment is usually always made on the last working day of the month for the following month. The dates are noted on the approval notice.
However, approval can only be granted once the core information to determine your individual needs has been submitted. At the moment, the completed main application suffices for this purpose.
Even after approval, you will highly likely be asked to submit documents. Unfortunately, such letters are often written in difficult-to-understand ‘officialese’ German. If you do not understand something, call the hotline (UKR: 0049 9111 787 915) for queries, write an email or make an appointment with a caseworker.
The only important thing is that you get back to them. Otherwise there may be payment issues and processing delays.