vCenter Appliance 5.1 and Orchestrator

I am confused a little and I can't seem to find answers in any documentation.

I have the vCenter Appliance 5.1 installed and configured.  I see Orchestrator is an option in the web client.

First question - how come it isn't available in the vSphere client?

Second question - I read docs that talk about the Orchestrator appliance.  But it seems to be built into the the version of the vCenter Appliance that I have deployed (VMware-vCenter-Server-Appliance-5.1.0.10100-1123965_OVF10)  Do I need to deploy an Orchestrator appliance too, or is this one that is built in going to work.

I need to build what amounts to a sandbox for some of my users to spin up VMs for testing.

Thanks