How is licensing for BM handled now? It's per user, correct?

Let's say that I have a 100 user BM 3.7 setup, does this mean that I
can
setup a VPN site to site without any additional licenses? If so, how
do I
accomplish this?

I am in the beginning stages of trying this and I couldn't see how to
assign
the other server as one of the servers.

Thanks,
Dan.