If you need to remove an entire page from your school website, click on 'Entries' in your left hand menu.
Navigate to the page you'd like to remove and then click on it. On the right hand side, one of your options should be 'Enabled'. The button should appear green when you first view the page. Click on it so that it turns grey, as per the below example.
Click 'Save'. Your page will now disappear from your website, but will be available in Craft in case you ever need to make it live or access the content again.
As you can see, the dot beside the removed article is displaying as grey as it has been disabled. The article should no longer show on your eduSITE.