How do I join/create a group ride?

Sorry if this is overly obvious, but cannot find how to ride with a group - can someone help me here so I can get in on a group that circles around 7-9 mins per loop?

Your best option is probably the Zwift Riders group on Facebook.

Uhm, Facebook? what’s that? 

I would agree the ability to find groups would be nice, but I have often found that after a lap or 2 I tend to find a few people who seem to be riding a similar pace.  In a couple of occasions I have actually rode along for a while/ maybe a lap or so with the same people/ person.  I am not certain how much the physics engine really works for drafting but I do try to take the front from time to time similar to on the road, but it is much harder to maintain your position than it is on the road.  It tends to be the front rider does not ease off to drop back but rather the back rider has to actually overtake.  With time I think this sort of thing will come.