Gandalf was out walking one day when he came upon a horde of orcs camping out. Gandalf decided to get a party together and slay the orcs. Gandalf gathers his forces and proceeds to slay the orcs. A few orcs escape and make it back to their establishment where they mount up forces and create a counter attack.
The influence is Gandalf stumbling upon the horde of orcs. The event is Gandalf and the party slaughtering the orcs. The outcome is the orcs mount a counter attack since they are pissed.
The influence is Gandalf stumbling upon the horde of orcs. The event is Gandalf and the party slaughtering the orcs. The outcome is the orcs mount a counter attack since they are pissed.
A second scenario is orcs attack the Gondor while Gandalf is in it. He gets out his sword and begins to slaughter all of the orcs that come into his view. The orcs retreat in haste before more of them are killed.
The influence is the orcs attacking Gondor where Gandalf is staying. The event is Gandalf slaying more orcs. The outcome is the orcs retreat and back out of Gondor.
Another scenario is when Gandalf and the Gondorians mount an attack on the gates of Mordor. Gandalf yet again slays tons of orcs. This leads to Frodo being able to get to Mount Doom and destroy the "one ring" and in turn destroy Sauron and his forces.
The influence is the attack on the gates of Mordor. The event is Gandalf slaying hordes of orcs. The outcome is Frodo destroying the "one ring" and obliterating the forces of Sauron.