Hi Farah @biijeeyjeey ,
If I understand it correctly, you have Filled your Faces incorrectly and now, if you Move your Isetted Circle down in Z, it ‘hides’ below another Face. It’s a bit hard to explain, but maybe this picture helps:

And there is a known limitation, with the Site, where you can’t add an image in the first post in a thread, asked directly under a Lesson. If you answer yourself, you can add images, like Sascha pointed out.