Coding needed done for Opencart Theme

We have Opencart new site in progress with a purchased theme but need some code added/changed/edited to add new Sub-Categories to top menu. The theme only has top menu and not the side and standard option in Opencart is Menu - Sub Menu. We would like another 3 extra layers to have - category > sub category > sub-sub category > sub-sub-sub category > sub-sub-sub-sub category. Would need it optionable so as not to have it show all but only as an option to show the extra sub-category. Opencart Theme is Everashop. Thank you :)