Refer to product guides
VCS Administrator guide
Page 166 onwards talks about running FireDrill using Java console
Page 467 talks about setting up DR firedrill
Note Page 166 references a Virtual firedrill (sometimes called HA firedrill) - this performs checks on the non-live nodes in a cluster to check they are capable of running the service group - see "About infrastructure checks and fixes for supported agents" on page 319. This works if you have VVR in an RDC, but I am not sure if this actually works with GCO.
A DR firedrill on Page 467 is completely different - this actually onlines the service group at the DR site on a snapshot of the data.