Menu sections not showing for creating sub menu

Hello,

I want to create a submenu from menu sections in food menu the problem is my menu sections and menu labels is not showing when I want to add the menu(in the appearance-menu), so I cannot add to the sub item, is this a problem with the theme or the jetpack plugin?

Also, if I want to add the submenu linking to specific menu sections in the front page is it possible?

Thank you so much for the help