Second menu item from demo named "Social Media" with tabs may looks complicated to build, but it's not.

See on below images how we made it:

First, create SP Tabbed Articles module with those settings, of course , do not forget about creating articles and category for them before.

Second, Create a new menu item, it can be Category Blog as we used. Fill first tab "Details", save settings.

Then open last tab "Helix Megamenu Options" where you have to move module SP Tabbed Articles into module area.