Hi lulubug83,
in your template back-end your Home menu item is assigned to the Homepage profile and in this profile setting the “Hide Main content block” is set to Yes that meant the Main content section would be hidden on the homepage.
When you clicked one of the content items in the slider it also bring you to the homepage with the big blank space (the section where the main content should be) that because there are not any menu items are pointing to those articles and they have been opened at the homepage.
In such a case you just need to create a menu item that point directly to those articles or point to the category in which they belong to then you do not assign any modules to display under the new menu item.
I hope you got the idea !