I've created two new boards but I seem stuck in boardid=1. How do I navigate to the other boards?

I'd like to create the structure below. Bolded items can only be created by an admin. Things not in bold can be created by regular users. The ">>" were meant to be an indentation but the indents were stripped out of the post.

I guess the structure below is:

Subject = board

Sx-Subx = category

User-Createdx=forum

I'm not sure if the above is the best structure for what I'm after. Subject2 is the most complex.

Subject1

>> S1-Sub1

>> user post

>> user post

>> S1-Sub2

>> user post

>> user post

>> S1-Sub3

>> user post

>> user post

Subject2

>> S2-Sub1

>> User-Created1

>>>> user post

>>>> user post

>>>> user post

>> S2-Sub2

>> User-Created2

>>>> user post

>>>> user post

Subject3

>> S3-Sub1

>> user post

>> user post

>> S3-Sub2

>> user post

>> S3-Sub3

>> user post

>> user post

or

or

....