Flex Slider Change Stock Images

Hi,

I am very new to wordpress, I recently installed the Argo Eshop theme https://alexgurghis.com/themes/argo-eshop/

which comes with a flex slider as you can see from the homepage, I manage to successfully add the slider to my new static page but however I have now idea how to change the stock images that come with the slider to my own images!

Any help is much appreciated thank you!