How to make Appendices behave like sections in TOC
I would like my appendices to behave like sections under the TOC but keep them as chapters in my document.

Here is a MWE of my current structure:

    \documentclass[11pt,a4paper,oneside,openright]{book}

    \begin{document}

    \tableofcontents

    \chapter{Introduction}
    \section{Section 1}

    \chapter{Literature Review}
    \section{Section 2}

    \chapter{Methodology and Data}
    \section{Section 3}

    \chapter{Results}
    \section{Section 4}

    \chapter{Conclusion}
    \section{Section 5}

    \appendix
    \addcontentsline{toc}{chapter}{Appendices}

    \chapter{First Appendix}

    \chapter{Second Appendix}

    \end{document}

I would like to indent the two appendices in the TOC to fall under the \addcontentsline entry as sections.

I have tried to do this by making the appendices into actual sections, but when I do this I get entries like '.A' and '.B' which is untidy. I'd like to keep the typical alph list for my appendices.

i.e.

    Contents
    
    1   Introdution
        1.1   Section 1

    ...    

    Appendices
        A. First Appendix
        B. second Appendix

Has anyone else tried to format their TOC with appendices in this way?
How to make Appendices behave like sections in TOC
===

I would like my appendices to behave like sections under the TOC but keep them as chapters in my document.

Here is a MWE of my current structure:

    \documentclass[11pt,a4paper,oneside,openright]{book}

    \begin{document}

    \tableofcontents

    \chapter{Introduction}
    \section{Section 1}

    \chapter{Literature Review}
    \section{Section 2}

    \chapter{Methodology and Data}
    \section{Section 3}

    \chapter{Results}
    \section{Section 4}

    \chapter{Conclusion}
    \section{Section 5}

    \appendix
    \addcontentsline{toc}{chapter}{Appendices}

    \chapter{First Appendix}

    \chapter{Second Appendix}

    \end{document}

I would like to indent the two appendices in the TOC to fall under the \addcontentsline entry as sections.

I have tried to do this by making the appendices into actual sections, but when I do this I get entries like '.A' and '.B' which is untidy. I'd like to keep the typical alph list for my appendices.

i.e.

    Contents
    
    1   Introdution
        1.1   Section 1

    ...    

    Appendices
        A. First Appendix
        B. second Appendix

Has anyone else tried to format their TOC with appendices in this way?