Hi! Welcome to the forum!
I would press the reset all code button first to put the lesson back to its original state.
Now, lets review the instructions.
Find the h1 element and change its text to:
CatPhotoApp
You do not need to add a new h1 element. You must find the existing h1 element that says ‘Hello World’ and change the text in the middle to ‘CatPhotoApp’.