The error message tells you the sections that are causing you to not pass this test:
Read the error message explanation very closely:
“Each element with the class of “main-section” should also have an id comprised of the innerText contained within it, with underscores in place of spaces.”
As far as advice, you need to make this responsive. Narrow your browser as far as it will go. You’ll see the horizontal scroll bar and when you scroll to the right the content flows under the side menu and is also visible. At narrower widths you can’t keep the side menu visible like that.