In your Floranext dashboard, go to Website > Content > Pages > All Pages and choose the page with no name (the URL key should show as Home). If you can't see a page fitting this description, let a Floranext agent know so they can enable it for you.
Editing this page allows you to add content that will show up below the banner area on your front page, above the products.
As a note, when you're editing the page, its title may show up as . This is normal, this is the character for an empty space. You may choose to keep it as the empty space so there isn't an extraneous page title at the top of the content you add.