Access to subcategories

Hello
I want to create an entry where I can show access to the subcategories of a category, that is, can show the titles and a image of subcategories.

The way Visual Composer have to work on blocks is to call the categories for to download all their posts, but not show an access to that category.

I have, for example, the top category “Areas” and several subcategories among which are “Astronomy”, “Biology”, Social Sciences “, etc.
When I click on” Areas” I want to go to a page where I can access to “Astronomy”,”Biology”,”Social Sciences”, etc., and NOT to all post of “Astronomy”, “Biology”, “Social Sciences”, etc.

I could do a independent access trough image (I think) but the behavior in mobil is not good.

This is because in my main menu I have two drop-down items, and one of them shows subcategories, but these are not visible in the mobil.
I have activated “Mobile theme” and I do not see the possibility of accessing to these subcategories from the cell phone.
I think creating a post with access to the subcategories would be solved.

I have the same kind of problem… very curious about the answer

Well, I was thinking if I duplicate the main menu and assign the new main menu to mobile…is this possible? Where can I assign a new custom menu as main menu to mobile?
I ask this because I think the solution would be to create a drop-down menu to my first item menu “Areas” with the subcategories in sub-items in drop-down.
In this way the user of mobile could access to subcategories in a clean way
I hope your help.