Thanks to Matt D’Aquino of Beyond Grappling for this nice analysis. He covers the grips, the o-uchi attack to square up his opponent, and the finish.
I would add one thing: notice Ono’s standing leg during the osoto attack. Hop-hop-hop. First he hooks his right leg behind his opponent, and to finish the throw he does three little hops. In order to finish Ono’s left leg must be as close as possible to his opponent’s right leg. Some people call that a ken-ken osoto gari.
Enjoy! And check out Beyond Grappling youtube channel.