When using the ACM-Reference-Format bibliography style with ACM sigconf templates on Overleaf, the reference list is sorted alphabetically by author. Consequently, numeric citations in the body may appear out of sequence relative to the bibliography:

Recent studies [3, 1, 4] indicate...

Switching to an unsorted style restores the sequence but removes required ACM formatting:

% \bibliographystyle{ACM-Reference-Format}
\bibliographystyle{unsrt}
\bibliography{refs}

Since unsrt violates submission guidelines, inline the generated bibliography and reorder it manually instead.

Compile the document initially with the official style:

\bibliographystyle{ACM-Reference-Format}
\bibliography{refs}

After a successful build, open the Overleaf log panel, scroll to the bottom of the output list, and download output.bbl from Other logs and files. The downloaded file contains a thebibliography environment:

\begin{thebibliography}{12}

\ifx \showDOI \undefined \def \showDOI #1{#1}\fi
\providecommand\bibfield[2]{#2}
\providecommand\bibinfo[2]{#2}
\providecommand\natexlab[1]{#1}

\bibitem[Adams et~al\mbox{.}(2023)]%
        {adams2023federated}
\bibfield{author}{\bibinfo{person}{John Adams}, \bibinfo{person}{Jane Baker}, {and} \bibinfo{person}{Chris Chen}.} \bibinfo{year}{2023}\natexlab{}.
\newblock \showarticletitle{Federated Learning over Heterogeneous Networks}. In \bibinfo{booktitle}{\emph{Proc. of the ACM SIGCOMM Conf.}}, \bibinfo{publisher}{ACM}, \bibinfo{pages}{15--29}.
\newblock
\urldef\tempurl%
\url{https://doi.org/10.1145/3603269.3604852}
\showDOI{\tempurl}

\bibitem[Davis(2024)]%
        {davis2024quantum}
\bibfield{author}{\bibinfo{person}{Laura Davis}.} \bibinfo{year}{2024}\natexlab{}.
\newblock \showarticletitle{Quantum Error Correction for Communication}. In \bibinfo{booktitle}{\emph{Proc. of the IEEE Int. Conf. on Computer Communications (INFOCOM)}}, \bibinfo{publisher}{IEEE}, \bibinfo{pages}{112--120}.
\newblock
\urldef\tempurl%
\url{https://doi.org/10.1109/INFOCOMXXXXX.2024.XXXXXXX}
\showDOI{\tempurl}

\end{thebibliography}

The \bibitem blocks in this file follow alphabetical order. Reorder these blocks so that the first \bibitem corresponds to the first citation appearing in the manuscript, the second block to the second citation, and so on. Leave the internal markup of each entry unchanged.

After reordering, copy the entire file contents and paste them into the main LaTeX document at the desired bibliography location. Disable the original bibliography commands:

% \bibliographystyle{ACM-Reference-Format}
% \bibliography{refs}

Then insert the copied environment directly below:

% \bibliographystyle{ACM-Reference-Format}
% \bibliography{refs}

\begin{thebibliography}{12}
\ifx \showDOI \undefined \def \showDOI #1{#1}\fi
\providecommand\bibfield[2]{#2}
\providecommand\bibinfo[2]{#2}
\providecommand\natexlab[1]{#1}

\bibitem[Davis(2024)]%
        {davis2024quantum}
...
\bibitem[Adams et~al\mbox{.}(2023)]%
        {adams2023federated}
...
\end{thebibliography}

A subsequent compilation will now display citations in ascending numerical order while retaining the exact ACM reference layout.