This is a missing piece on the internet - the poudriere Apache vhost config.
You only need to adjust the datadir path (where it drops the packages) and your servername.
Adjust the /usr/local/etc/poudriere.conf URI setting to match with your vhosts' ServerName directive.
The Web interface is straight out of a UX nightmares book. Make sure to spend some time with it right away. It does have some nice features, but you need to learn how to properly filter/sort to get useful info.
Here's another article I'm working on that has a lot of extra info about Poudriere: