Edit portfolio page with visual composer

Dear Sirs,

How can i edit the portfolio page (i mean the portfolio page, not the portfolio grid page) with the visual composer?
When i try to edit the portfolio page, i can only see the Backend Editor button.
How can i change the upper right dropdown menu (graphic design, video animation etc..) of the portfolio page?
How can i change the arrangement of the portolio’s page boxes?

Best Regards,
Angelo