PRODUCT placement 5col

[DOA]

Hi

1. HOW to create 5 or more product columns (i have expanded cental column(central+right one));
because in css files there is only width which i can change but if i do, nothing happens and the are still 4 columns , but if i make width smaller magically 4 columns become 3,2 or 1

2.Why when i try to create central column bigger than 775px it slides "under" left column?

3.Is it ok to expand central column by only increasing width in global.css ?

I hope you can help !
Sincerely,
greed