This package uses the INSTANCE_HOME installation method, as described at
http://www.zope.org/Members/4am/instancehome.  This allows you to install the
Zope package once and create as many sites as you want without changing your
core Zope installation.

Have a look at /usr/local/lib/zope/doc/README.OpenBSD
to see how to create your instance and have it start at boot time.
