How to require a quest to be turned in?

[bonusminutes]

I have an event, that when the action key is used on, starts a dialogue and offers a quest to kill 5 of an enemy. I want the rewards to be given once the 5 enemies are killed AND THEN the player returns to the event and speaks with it. So far, the quest gives rewards immediately upon killing the 5th enemy.

Thanks!

[bonusminutes]

Figured this one out on my own.
My quest was to kill 5 crabs.

In the quest editor, I set the tasks for the quest as:
Kill NPC(s) [Crab x5]
Event Driven-

I also made sure that when I was in the quest editor, I used the Edit Quest Completion Event button to set a reward, which was:

 

Then I set up the actual event that triggers the quest as such:

 

The quest offer screen asked to start the quest and on accepting it began. Attempting to speak to the event NPC again didnt result in any issues and the event driven task couldnt be completed until the 5 crabs were slain. When the 5 crabs were slain, the reward was granted, the reward text appeared, and the quest could be repeated.