Hi Luca, almost there. You need to enable section numbering for what you want to work so set num:t in the options.
If you want second level headings to appear as well, add #+latex_header: \AtBeginSubsection[]{\begin{frame}BARRRRR\end{frame}} -- : Professor Eric S Fraga, http://www.homepages.ucl.ac.uk/~ucecesf : PGP/GPG key: 8F5C 279D 3907 E14A 5C29 570D C891 93D8 FFFC F67D : Use plain text email when possible: https://useplaintext.email/