You can set the general depth of the contents listing using:

\setcounter{tocdepth}{n} where n is the level, starting with 0 (chapters only)

and the general depth subsection headings using:

\setcounter{secnumdepth}{n} where n is the level, starting with 0 (chapters only)

in the preamble (i.e. before \begin{document}. This will work for the whole document.