For new installations:
chown ${VHOST_SERVER_UID}:${VHOST_SERVER_GID} ${MY_INSTALLDIR}/settings.php
find ${MY_INSTALLDIR}/frontend -name settings.php -exec chown ${VHOST_SERVER_UID}:${VHOST_SERVER_GID} {} \;
find ${MY_INSTALLDIR}/{data,temp} -type d -exec chown ${VHOST_SERVER_UID}:${VHOST_SERVER_GID} {} \;

Browse to http://yourhost/${PN}

You'll be taken through the web based installer. The web based installer is
fully documented and should describe each option that you'll have along the
way.