I can't access Mediafire due to restrictions on the network where I work, however, from your description, I think I know what the problem is.
After Effects does not work the way you think it does. It is way more complicated. Template-makers try to make it easy to put your own content in their projects, but modifying them can be a major pain. What are you doing when you are trying to make your own "placeholders"?
That tutorial won't help you at all. That's for folks who are creating their own work in AE, not adding to templates.
I can't offer you any specific help without looking at your template file, but it's likely a lot more complicated to add stuff to it than you think it is. After Effects doesn't go, "lets animate every placeholder". After Effects only does what it is specifically made to do. A solution for you might be to simply create several versions of your project, each one with 4 elements in it until you've shown all the things you want to show. Then, you can render each one out and put them together in an editing program like Premiere.
If you want to learn how to actually work with After Effects, start here: Getting started with After Effects