When visiting the theme for the first time, please note that what is shown on the screen is not your actual homepage.
To use the homepage template, go to Pages › Add New, choose a title, for example "Home", fill the page content with your own content(this is what will appear under the slider - in the theme's body, not in the slider) and leave Default Template in the Page Attributes box.
Under the WordPress content editor you will find a section named "Page Parameters" where you can choose to enable or disable the page title, custom content for the page title, enable or disable the sidebar, sidebar alignment and also whether you want to display the slider in the header or not.
Choose the settings that you prefer and save the page.