Make a different element appear after a certain amount of time

Hi everyone! I’m trying to use the set interval function to make a different element appear every 15 seconds but I’m struggling. For example, I want 1 element to appear, then that element to hide and another one appears, then that one hides and another one appears. I want it to loop indefinitely. Please HELP! :grinning:

https://russian-dima.wixsite.com/meinewebsite/test-1