relationsViewId allows you to tie the relations definition in plugin.xml to the view extension id ending with ".related" that it automatically created by the objectViewTemplate. So you don't need to create anything it's already done for you :-) Just make sure that the relationsViewId value is {namespace}.related
Here is the snippet from the chassis-app plugin.xml (where the objectViewTemplate namespace is "com.vmware.samples.chassis")
<extension id="com.vmware.samples.relateditems.specs.chassis">
<extendedPoint>vise.relateditems.specs</extendedPoint>
<object>
<type>samples:Chassis</type>
<!-- relationsViewId references the "related items view" extension created by the objectViewTemplate -->
<relationsViewId>com.vmware.samples.chassis.related</relationsViewId>
<relationSpecs>
....