Visual Composer add-on compatibility, Taglines and Expandable Area styles

how do you add other plugins(addon) to visual composer within the theme? I bought a plugin(addon) from visual composer store to enhance some of the gallery features and functionality an it would not work within the theme frame work

I could not find where to change the back ground picture (the gray one )in the theme anon one of my pages i have a blue line running under the gray on my portfolio page
(https://graphxsamurai.com/portfolio/portfolio-2/)

in the menu icon on the far right ……when you are in there i don’t see where you go to make changes to this menu ….move stuff around/change the back ground/remove things

I really like the theme but these have been my frustration with it that i can not figure out