I want to make a shooting NPC that shoots missiles for a boss battle. Can anyone help?
You're going to want to look into A* pathfinding and raycasting for the shooting. You're not very likely to find someone on here who is going to help you by giving you a read script though.
Considering the nature of the question I am assuming you are not a very experienced scripter yet. If you are, my bad, however I would suggest you would start with some more simple tasks. For example leave the pathfinding out for now and make it move in random directions.
There's a tutorial on the wiki about raycasting.