A page4 web page consists of different areas. There is a content area on each page. When you move content from the sidebar to the content area of the page, the placeholder becomes green and tells you that you are moving the content to the content area and that this content will only be visible on this page.
In addition to the content area, there are two sidebars on the left and right. The special thing about a sidebar is that although it has a content area, the content in a sidebar remains identical on every page you call up. So there is not a sidebar for each page but the sidebar is global. If you move content to the sidebar, the placeholder turns blue and signals you that you are now moving content to an area that is visible on every page.
Additionally, there is footer 1, which behaves exactly like a sidebar, but is arranged below a page. Again, the placeholder blue.
When content that should only be displayed on one page is visible on each page, then you are either in a sidebar or in footer 1 Just go to the page on which the content should be displayed and move the content from the sidebar or the footer to the page area.