Don't laugh. I'm younger than 13. I checked out this FPS tutorial (http://download.unity3d.com/support/resources/files/FPS_Tutorial_1.pdf), and I understand it except for one part. It says go to Objects/Mainlevelmesh/Mainlevelmesh. I can't find this "objects" folder in my projects tab under Standard assets. How do I find it? Thanks.
I guess this objects is not under the standard assets, cause standard assets are... standard assets. You can use the finder on the Project window:
Look at the right side of the Create button, its a search bar.
That's because you're looking in the Standard Assets folder; what you need to do is download the tutorial folder (Found here, second link from the bottom), open the downloaded project with Unity, and the level mesh will be inside that folder.
The reason it isn't in Standard Assets is, like Borgo said, the Standard Assets are, well, standard. They don't include the tutorials; they're just the basic assets that all default Unity projects come with.
By the way, I'm impressed with your grammar. Welcome to Unity!