A cleric has the power to force away certain category of monsters called the “Undead” (skeletons, zombies, ghouls, mummies, and other more powerful types). To use this ability, the play must only declare that they shall “Turn Undead” and be within 30 feet of the monsters.
What is Turned?
Turned undead flee by the fastest means available to them. They will not touch the cleric, and will flee as far from them as possible. If they cannot flee, they cower.
If anyone, other than the turning cleric, approaches the undead within 10 feet will cause the undead to immediately overcome their repulsion and the undead will attack as normal.
All attacks made by the cleric vs turned undead are made at Advantage.
Effects of turning last for 1 minute (10 rounds).
How Does It Work?
The base roll to turn undead is 10 + the hit dice of the monster. So a Skeleton would have a turn value of 11. The cleric then rolls d20 and adds their Wisdom (and focus) to effect the undead. The cleric would make this check vs each undead within the 30 foot range.
To destroy the undead, rather than turn them, the cleric must exceed the target number of 15 + the hit dice of the monster.