Oxygen's visual editor can be opened by clicking the Edit with Oxygen button. The button appears on the Edit screen for posts, pages, and all custom post types.
To open Oxygen on a Page, follow these steps.
Go to the Pages screen in the WordPress admin panel
If the page is not yet created, click Add New button. Then click Save Draft or Publish. If the page is already created, point to its title and click Edit link.
Click Edit with Oxygen button to open the page in Oxygen.