Adding child nodes to child nodes in TikZ Mindmap

Question

I'm trying to build a mind map in TikZ and am having numerous problems.

I have only a very basic grasp of TeX and would like some help.

I found a source and replaced text to create my first steps.

Now I'd like:

1. To add child nodes to my child nodes

2. A bigger canvas

How do I do them?

Source code:

\documentclass{article}

    \usepackage{tikz}
    \usetikzlibrary{mindmap,trees}

    \begin{document}
    \begin{tikzpicture}
      \path[mindmap,concept color=black,text=white]
        node[concept] {Die Wahrnehmung}
        [clockwise from=0]
        child[concept color=green!50!black] {
          node[concept] {Sensorische Prozesse}
          [clockwise from=90]
          child { node[concept] {Sinnes\-organe} }
          child { node[concept] {Schwellen} 
  child {node[concept] {absolute Schwelle}}
  child {node[concept] {Unterschiedsschwelle}}
  }
  child { node[concept] {Optische Täuschungen aufgrund sensorischer Prozesse} 
    }
} 
child[concept color=blue] {
  node[concept] {Organisation}
  [clockwise from=-30]
  child { node[concept] {Hauptsatz} }
  child { node[concept] {Gestaltgesetze} }
}
child[concept color=red] { node[concept] {Klassifikation} };
\end{tikzpicture}
\end{document}

Answer 1

Just nest further, add children after nodes. The tikzpicture canvas will be extended. Here's a small example with four levels. You can extend it, add and modify styles.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{mindmap}
\begin{document}
\begin{tikzpicture}
  \path[mindmap,concept color=blue,text=white,
    level 1 concept/.append style=
      {every child/.style={concept color=blue!70},sibling angle=-30}]
      node[concept] {\Huge\bfseries PGF}[clockwise from=0]
        child {node[concept]{\LARGE Ti\emph{k}Z}
            child{node[concept] {\large arrows}
                child {node[concept] {thick}}
                child {node[concept] {thin}}}
            child{node[concept] {\large mindmap}}
            child{node[concept] {\large plots}} };
\end{tikzpicture}
\end{document}