I want to start with my first LaTeX project and I am using a couple of templates, but I've encountered a problem. The template seems to be using:

\tableofcontents

For the table of contents, it looks good however I want to change the header from 'Contents' to something else, like 'Inhoudsopgave', but I can't seem to do that.

What is the solution?

In some cases you can use the command \renewcommand{\contentsname}{Inhoudsopgave}.

In other cases (when you only want to change the language settings to Dutch) you should rather use a package for this cause (I recommend babel) like this.

\documentclass{book}

\usepackage[dutch]{babel}

\begin{document}

\tableofcontents

\end{document}