FPS camera doesn't work

[Rucliwood]

I am making a FPS game and I tried this script:

The First Person Element Of A First Person Shooter

This guide was originally written for scriptinghelpers. The original can be found here. In this post we will be talking about creating our very own filtering enabled friendly first person shooter (FPS) game. I do want to make clear though that I won’t be covering how to actually make the weapon shoot in this article. All we are going to be covering is the visuals meaning having the character aim down sights, look up and down, etc. Maybe we’ll talk about shooting another day. Things to take …

But I couldn’t see the gun.
What do I need to do? Thanks!