I am not the theme author, but It uses a series of ‘slider’ pages. Do you have the Demo content installed? If not install that to get you started so you understand the make up. and then in the Appearance > Customize > Featured Slider Options, turn the slider on and ensure the pages are the Fashion, Hoodies, Jacket, Rings pages. You can set up to 5 slides with the built in slider.
Otherwise use the Slider Revolution plugin for more flexibility and animation styles.