ettercap -T -q -P dns_spoof. would be enough in a different xterm.
Dns spoofing - be it with ettercap or DNSspoof - is a very messy thing. You don't want to use that for blocking sites in an office... And with a telephone ?!

I'd help you with DNS spoofing, but it seems it's really not what you're looking for.

Again, there is DNS spoofing in Yamas, so even without the code you should be able to comprehend how it works. I made this script for people to learn and get things easily. Did you run it or just watched the video ?