The download link points to a live image so you just need to point to it as
the root disk of your hypervisor's guest and off you go.
Unfortunately there's a catch, the 4GB fs is not big enough and the provided
packages are huge here because they're unstripped.

The quickest option is to attach a secondary disk and mount that to /usr/pkg
or follow the steps in the "Install" link on the website to copy the contents
of the image you downloaded to the new disk & boot from your new disk.

Note the root password in viewpoint-password.txt which is included the
download.
This is due to not being able to have an account without a password by default
and it was safer to do this than to poke new holes to accomodate that and
creating bigger problems down the line.
There is nothing is listening on the network by default and networking is not  
working either. sshd's PermitRootLogin setting is set to prohibit-password as
default.
Once you have logged in as root, note the message printed from /etc/motd to
get going.

To convert the downloaded raw image to your hypervisor's native format the
qemu-img utility which comes with qemu can be used.
qemu-img convert viewpoint-0.0.img -O vmdk viewpoint-0.0.vmdk

Booting the image with VirtualBox
Convert the viewpoint-0.0.img to vmdk format using qemu-img
When creating a new VM using the wizard, choose "Use an existing virtual hard
disk file" and point to the vmdk file you created.
Todo: Add instructions for creating a VM with VBoxManage.

Booting the image with Qemu
qemu-system-x86_64 -hda viewpoint-0.0.img -hdb secondary.img -m 1G -accel kvm \
   -net nic -vga std

Booting the image with bhyve using grub2-bhyve
grub-bhyve -m viewpoint.map -r hd0,msdos1 -M 1G viewpoint
viewpoint.map contains '(hd0) /path/to/viewpoint-0.0.img' (without single
quotes)
bhyve -A -H -P -c 1 -m 1G -s0:0,hostbridge -s 2:0,ahci-hd,viewpoint-0.0.img \
   -s 31,lpc -l com1,stdio viewpoint