how to list the children of selected node in oracle webcenter portal

I need to add an additional navigation to my oracle webcenter portal project. This additional navigation should show the children of the selected node in navigation bar. Also, this additional navigation is should be in a left sidebar. How can i do this ?

     <af:panelGroupLayout layout="vertical">

 <c:forEach var="node" varStatus="vs" items="#{navigationContext.currentModel.listModel['startNode=/, includeStartNode=false']}">
        <c:if test="${node.selected}">
            <c:set value="${node.children}" var="childNodes" scope="session"/>
        </c:if>               
</c:forEach>

<c:if test="${childNodes ne null}">
    <c:set var="childNodes" value="${navigationContext.currentModel.currentSelection.parent.children}"/>
</c:if>
<c:forEach items="#{childNodes}" var="node2">
                <af:commandImageLink id="cil3" text="#{node2.title}"
                                     actionListener="#{navigationContext.processAction}"
                                     action="pprnav"
                                     icon="#{node2.attributes[pageFlowScope.tnBean.iconKey]}"
                                     disabled="#{not node2.navigable}"
                                     inlineStyle="#{node2.onSelectedPath ? 'font-weight:bold;' : ''}">
                  <f:attribute name="node" value="#{node2}"/>
                </af:commandImageLink>
</c:forEach>

</af:panelGroupLayout>