Navigation using folders problems ! please help

Hi guys I am new and this is something I have spent two weeks trying to achieve. I am an intermediate asp user.

I am attempting to make a sub navigation with great difficulty.
Basically I have the main navigation like this:-

Home | About Us | Services | Products | Contact Us

And then I would have my sub level navigation. In total I have three levels of navigation
only. So if we had of clicked About Us we would then have the following sub navigation:

Meet the Team
Management

If we clicked on the level two navigation "Meet the Team" we would have a setup like below:

Meet the Team
>Link one
>Link two
>Link Three

Management

But I have no idea how to approach this task. I have spent two weeks trying everything.
I am clueless.

My structure will be in a folder based environment like so:

about_us
about_us/meet_the_team/
about_us/meet_the_team/Link_one/
about_us/meet_the_team/Link_two/
about_us/meet_the_team/Link_three/

And so on. So hopefully this will make sense.