CQWP not rendering description

Question

Am fairly new to SP, but managed to create a custom layout with additional slots in ItemStyle.xsl

I have slots for Title, byline and others which are working fine, but the Description is blank.

            <div class="description">
                <xsl:value-of select="@Description" /> 
            </div>   

I've read your post, but am not sure where to change the DataMappings, and DataMappingViewFields.

Content Query Web Part not rendering calendar list description field