Freebsd xen host dom0

[Steven Friedrich]

I have a new HP Slimline Desktop 290-p0014 which features an Intel i7-8700
and no com ports.
I am hoping to create a FreeBSD xen host to explore various FreeBSD and
Linux distros.
I was following along with chapter 21.8 FreeBSD as a Xen -Host.
I am using handbook rev 52113 modified on 2018-08-12 08:50:20 by eadler.
I did a fresh install of FreeBSD 11.2, pkg install xen and when I rebooted
it claimed:
don't know how to load module '/boot/xen'
don't know how to load module '/boot/xen'
(odd that it repeated that)
can't load 'kernel'

I can boot and turn off booting the xen kernel and FreeBSD comes up fine.
I used file /boot/xen and it reveals xen is a ELF 32-bit LSB executable,
Intel 80386 version 1 (SYSV), statically linked, stripped
What am I doing wrong?
I have previous FreeBSD experience, but it was long ago.  I may have
forgotten more than I knew 8o)