Can some one tell me what is Section and grid
 

I am totally new to VB and i bought a suit license but i do not get it. To many things to touch i guess. What is the Section for and what is the grid in the admin? I guess i understand the category in the suit but it make no sense since the sections are all over the place.

I suggest you start with the documentation -
Welcome to the new CMS. Read me first.
Getting Started with CMS Documentation Files (PDF)

Look through the articles over on vb.com and you'll find many more.

I GET that section is a SECTION but what is the point really? if i try to change the category in section Travel i try to add Singapore and then i get two Singapore. When i click on the home page i click travel and i see all the category so whats the point to have a section?

Actually, I think most would say What is the Point of having Categories. I understand having Sections, but Categories have always seemed pretty useless to me (thus, I won't use them).

Right thats one way to see it, or if you click section you should only see the category from THAT section.