Use example:
<h:panelGrid id="myPanel" columns="4"
footerClass="myFooterCss" headerClass="myHeaderCss" columnClasses="column1Css,column2Css,column3Css">
<f:facet name="header">
<h:outputText value="Header content here" />
</f:facet>
<h:outputText value="1" />
<h:panelGroup>
<h:outputText value="2a" />
<h:outputText value="2b" />
</h:panelGroup>
<h:outputText value="3" />
<h:outputText value="4" />
<h:outputText value="5" />
<h:outputText value="6" />
<h:outputText value="7" />
<h:outputText value="8" />
<f:facet name="footer">
<h:outputText value="Footer content here" />
</f:facet>
</h:panelGrid>