XML : Relational database from XML

I am trying to learn to create a relational database schema from a given XML format. the format is as follows

   <product description:"Cardigan Sweater">   <catalog-item gender:"Men's ">    <item-number>QWZ5 67 1 </item-number>    <price>39.95</price>    <size description:"Medium">     <color>Red</color>     <color>BurgundY</color>     </size>     <size description:" Large ">      <color>Red</color>      <color>BurgundY</color>     <lsize>   </catalog-item>   <catalog_item gender"'Women's">    <item-number>RRX9 8 5 6</item-number>    <price>42.5O</Price>    <size description:"Medium">     <color>Red</color>     <color>Navy</color>     <color>Burgundy</color>     <color>Black</color>    </size>    <size description:" Extra Large ">     <color>Burgundy</color>     <color>Black</color>    </size>   </catalog_item>  </product>    

Any help would be appreciated