Document Classes ⇒ Numbering Appendix

[handel19]

Please tell me how I can number the appendix with arabic numbers (1,2,3).
I use

\appendix
\addtocontents{toc}{\protect\setChapterprefix{Appendix }}
\makeatletter
\renewcommand{\@chapapp}{Appendix \@arabic\c@section}
\makeatother

before Appendix, but it numbered with capital letters (A, B, C).