Homepage Feature images, link etc

Hi, Not sure if I am doing this correctly. But I installed this theme and I am trying to change the default feature thumbnail and slider image and content to my own, but so far nothing seems to work or load. I am going into, appearance, Theme Options, selecting Homepage settings tab, and choosing the image/link I am looking at switching. The issue is when I select add image, then go to media gallery, it does not allow me to select anything. With link for content, after I save the changes the changes are not saved. Not sure what's going on. Am I not in the right area to make these changes. Thx