I see

Well, let me try:
Each template is seperated into catagories to make the user understand what templates it under what catagory.
For Example:
Forum Home Page Templates contains a list of template which when edited, change the look of your main forum homepage.
forumhome is the main template for editing the forum homepage.
Get it?
Also, editing stuff like CSS values and anything contained in the head tags, can be found in
headinclude template.