If you can't install the suggested plugins you probably aren't submitting the installable zip. Inside the main file you downloaded from ThemeForest you will find a folder called Suggested Plugins that contain the plugin archives. Only in these archives, that you also have to unzip, will you find the installable zips and documentation of the plugins.

If you want to install the Visual Composer plugin for example, the correct path is "Marine WordPress Theme" > "Suggested Plugins" > "Visual Composer" > js_composer.zip.