Number only Appendix in Article

Question

I am using a customized style for my article, where section is the top header, and no numbering is made for sections, subsections...etc

I would like to keep it as it is, but, use an alphabetical numbering for my appendix.

Does anyone have a idea?

A MWE:

\documentclass[letterpaper,Arial,9pt]{sae} 
\usepackage{amsmath} 

\usepackage{lipsum}
\usepackage[titletoc,toc,title]{appendix}%5,page
\begin{document} 

kjasww
\section{section}

\lipsum[1]

\appendix
\setcounter{section}{0}
\renewcommand{\thesection}{\Alph{section}}
%\begin{appendices}
\begin{appendices}
\section{Appendix}
\lipsum[1]
\end{appendices}

The style file can be found here;

Answer 1

The sae document class contains the instruction

\setcounter{secnumdepth}{-2}

This instruction suppresses the numbering of all sectioning headers as low as part, which has level -1. The level of chapter is 0, that of section is 1, subsection is 2, etc.

To (re-)enable the numbering of section-level headers, you therefore need to provide the instruction

\setcounter{secnumdepth}{1} 

along with \appendix.