Ok lets go through this.....
Within the options of MediaBrowser ( Shift and 3 or Shift and 8 depending which build you are using ) go to the General tab ( the first one )
In there there is a setting for Initial Location.......this is by default set to MyVideos. This is where MediaBrowser will look for media by default and any vf ( virtual folder) files you have.
IMO the best way to organise Media Browser is not to have your media actually in that folder but in other folders/directories/disks/pc's and just put your vf files in there. You could always do it this the opposite way I suppose and change this Initial Location in the options to another foder on your PC that you create, then drop your vf files in there.
Create the vf files for the categories you want dispalyed on the first MediaBrowser screen , and within them point them to where your media is.
I have posted previously in here details of my vf files , You could have a vf file called movies.vf and within it point it to all your movie directories, and another called tv.vf and point it to all your tv directories.
Then on the first mediabrowser screen you will see two icons , one for tv and one for movies. Clicking either will take you to the appropriate media.
If you want to have fancy icons on these as I have done , drop the image you want to use somewhere ( it doesnt matter ) rename it folder.jpg ( obviously as they are all the same name you cant put them in the same directory, so a good idea to put them somewhere in the respective tv/movies folders ) then use image: command in vf file to point to it.
vf files are really powerful but are dependant on how you have your data organised. In my case I have a top level movie directory , with subdirectories of Adult films and kids films. I then use seperate vf files to point to each subdirectory so I get seperate folders for this on the main MB screen. But you could split your media up into any folders you like and have them as sepearate selections on the front screen.....for example by genre , by type ( ie HD, DVD, AVi etc )...its totally up to you how you organise your data , but by using vf files you can split them out for selection easily.
I hope that all makes some sense !
If it doesnt...the official WIKI for MEdiabrowser has some more info
HERE