After creating a child page, do not insert components. In General Settings, you can select "Link to External URL" or "Link to File".
If linking to a file, save the file as a PDF before uploading to make opening the document easier for parents and students. In General Settings, find the "Link to File" and upload the file just like attaching a document in your email.
If linking to an external URL, do not insert components. In General Settings, find the Link to External URL section and place the URL of the website you would like to link to.
You can see an example in dynamic navigation, titled External URL Example. If the link were to take you to a file, the file would open instead of new a website.