Do not edit this actual page. Copy it first. You will see that option on the left - options are copy or delete. The "hide in navigation" box is checked. That means it does NOT appear on the website. You can edit without time pressure.
Go back to PAGES (top of the page) You will see your newly created page copy appear at the bottom of the list of pages. Rename the page to your subject. Drag and drop it in the page listing to put it where you want it to go on the website. (It can be a drop down for a category or a new category entirely. The indent makes it a dropdown page) You are unlimited on the number of pages that can be created.
Once you are ready to have it appear on the website: Click PAGES Uncheck the "hide in navigation" white box under your page name It will immediately appear.