On a failure, a target is affected by this spell. Until the spell ends, you can use an action on each of your turns to designate a direction that is horizontal to you. Each affected target must use as much of its movement as possible to move in that direction on its next turn. It can take any actions before it moves. After moving in this way, it can make another saving throw to try to end the effect.
A target isn’t compelled to move into an obviously deadly hazard, such as a fire or a pit, but it will provoke opportunity attacks to move in the designated direction.