I think I know how to use \label{...} and \ref{...} But after changing the tex-file to pdf I have no possibility to click the refers. Once I get it. There were red frames around the clickable words, but i forget how I did this. There are to many possibilies to transform the tex-file. Which should I use to get the correct output? (I hope you understand the question)
Two things: (a) \usepackage{hyperref} and (b) you can find lots of tex users at tex.stackexchange.com