Clarity in Turret Defense Tutorial.

Has anyone been able to actually complete this tutorial? I get stuck on many things here and it makes a LOT of assumptions.

For example:
"add meshes that represent the tower as children of the GameObject" What does this mean exactly?
"Add a Tower component to the NewTower GameObject" What tower component? At what point did I create one in this tutorial? There are none included with the project, unless it's one of the very specifically named script components?

I stopped there.
Am I just very uneducated and therefore unable to understand these concepts or is this Tutorial basically useless?

 

I am having the same problem. any help would be appreciated