Folder structure and link problems

[sj_polanco]

Goodmorning everyone
I am working at designing a website in dreamweaver.
i have my index page in my root folder i also created subdirectories like, aboutus; contact; products. these subfolders contain pages.
my horizontal menu is javascript link to in an external file. i have a template which i intend to replicate. the links in the javascrpt are document relative. thus when i click on the menu on the pages within the subfolders it shows me Error page not found. the homepage link does not work because it is in the root.
let me indicate that i am using a link relative to document in Dreamweaver.
do i have to use link relative to siteroot or are there other ways of going about it?
i have seen sites like lynda dot com : lynda.com/Web-Interactive-training-tutorials/88-0.html and when you click on the homepage link it takes you back to the index in the root directories. that is what i want to achieve.

Secondly, how do i prevent a user from seeing the contents of the subdirectories if they simple drop off part of the URL for example
***crispshave.com/products/