Here is the whole thing explained with an example:
Development of category A:
- Budget January 2022: +100 EUR
- Expenditure January 2022: -10 EUR
- Budget February 2022: +100 EUR
- Expenditure February 2022: -50 EUR
- Budget March 2022: +100 EUR
- Expenditure March 2022: -25 EUR
=> Balance at the end of March 2022 = 215 EUR
Report at the end of March 2022:
Category A: 215 EUR
I hope it became clear what I need. I'm German and writing this post with the help of deepl, so it may be that I haven't found a thread in which my problem has already been solved - then feel free to post the link
Thank you very much for your support!