CMS I simply don't understand
 

Hello

I don't understand how SECTIONS works on CMS. This is the structure i have in my website:

News
News > Section1
News > Section1 > Sub-section
News > Section1 > Sub-section
News > Section2
News > Section2 > Sub-section
News > Section2 > Sub-section

Can somebody explain me why News is always the main section? Every time i submit a new article the only sections available are the blue ones. I can only assign:

• News
• Section1
• Section2

What about Sub-sections??? I think that the right structure is the following:

Section1
Section1 > Sub-section
Section1 > Sub-section
Section2
Section2 > Sub-section
Section2 > Sub-section

But how? Please explain me
Thank you