using sparql

Hi,

I am new to rdf and sparql and finding it hard to work on it in drupal as I could not find any tutorial for help.
I have downloaded the RDF, evoc,sparql, rdf cck modules. I have seen some powerpoints with page slide create sparql qurery with a box to write query and also provide end point. But I am not able to find it.

Am I missing any module here? Would really appreciate help on how to use sparql to query external databases.

Thanks
rpandey