Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
I belive in Urgot as a champion to stand a bit away, running in to swap if needed, but else just lobbing in the Corrosive Charge, spamming homing missiles at.. whatever you feel should have more holes to breathe through.
This build tells you to simply rely on your Q ability and with BoS, Trinity force, your masteries and Ghost, chase whoever that is running from you.
Runes for amror pen, since the Q ability is physical damage
And the specc for more ArP and CD reduction.
Urgot got a kinda bad manapool/regen, there for the mana runes and the Utility points in the mastery.