Edit the page content
Note: Page Titles are different than page names: page titles appear on top of the web pages, they should contain spaces. Page names are file names, they should not contain spaces.
You could disable this feature in the Navigation Settings and add links manually to the current site navigation. There are pages you want to create links in the page content and don't want them to automatically show on the left navigation. (View
Modifying navigation / Current navigation)
The link to the newly created page is automatically placed on the current site navigation bar after you published it.