Tiles are defined in WEB-INF/tiles.xml with the definition tag. Example:
<definition name="book" path="/headerMenuContentLayout.jsp">
<put name="header" value="/bookHeader.jsp"/>
<put name="menu" value="/bookMenu.jsp"/>
<put name="content" value="/bookContent.jsp"/>
</definition>
bookHeader.jsp, bookMenu.jsp, bookContent.jsp are the same as before.
headerMenuContentLayout.jsp (shown later) defines the reusable layout.