You have to duplicate your compositions in the project panel and not the timeline.
Templates can get terribly complex with many levels of precomps. You may need to duplicate several of them. The True Comp duplicator (a third-party script) could come in handy.
I have looked at a ton of videos and read several articles and I can't figure out how they are linked together.
Then you're looking at the wrong videos. As someone new to AE, you should really start here: Getting started with After Effects
Sorry, but simple possession of a template does not guarantee success in AE. There's a reason why there are templates -- using AE to its fullest can get VERY complicated. If template creation was easy everyone would make them and they'd be free.
Follow that link Szalam supplied -- you'll be glad you did.
I did duplicate the whole Text Precomp 7. But I need to replace Text 07 layer with Text 08. But even when I did that Line 3 which is a 3d object still points back to Text 07.
Text 01 Precomp 7 has 5 layers, 2 of them being Text 07. Even when duplicating it, I still need to replace the Text 07 layer.
I have taken the Lynda.com Adobe After Effect Essential Training and it went over 3D which is what layer 3and 5 are but as you can see item 2 is not even visible but layer 3 knows what the text is and is displaying it. What are the 2 images that are on the right side in what I have circled there?
Never mind I figured it out. All I had to do was drag the layer over top of the one that I wanted to replace and it picked up the attributes and replaced the Text 07. I got that information from looking at this link: After Effects Basics - Compositions & Pre-Composing which does something similar. I can't believe it was that easy. I still would like to know how it linked those 2 together but for now, what I need done works.