I hope you are well today and thank you for your question.
i would like to ask you how I can add new or edit the existing Gillion Templates in WP Bakery – http://prntscr.com/t4uo41.
You can achieve it as described on the below pages.
In addition, is there a way to hide/disable this tab (in case these templates are not editable).
There is no option to disable it so you have to develop custom code to disable it.
Developing custom code for custom functionality is beyond the scope of support that we provide here. Please see https://themeforest.net/item/gillion-multiconcept-blogmagazine-theme/19470306/support
If you are not a developer then you can consider hiring a developer to develop it for you. You can hire a developer from any freelance site. Shufflehound recommends the developer https://www.upwork.com/freelancers/~011652ffec8865c6d5
Thanks for your reply,
However, I can not achieve what i sent you in the screenshot http://prntscr.com/t4uo41 with the documentation in the links. I am asking how to achieve the custom templates (Gillion templates), with the image description, categories on the left etc.