Office 365 team rolling out the new updates to the SharePoint Online for the First Release Users. Learn here to become the first user to get the updates,
Visit Get Early updates before public release in Office 365 and follow the steps to become the first user to get the updates. If you are not an admin, check with administrator to apply the settings.
At present, some of the new look and feels are visible to the user and some of them are hidden from user. Instead of navigating to each page, the below are some lists of URL which we can directly enter and experience the modern UI updates in SharePoint online.
Get the new Home page
To view the List, Libraries & Add-ins in Site Contents page
To view the sub sites in Site Contents page
To view Recycle bin
To view Second stage recycle bin
Folder within List
https://<siteurl>.sharepoint.com/Lists/ListName/AllItems.aspx?id=<folder server-relative URL>
Folder within Library
https://<siteurl>.sharepoint.com/LibraryName/Forms/AllItems.aspx?id=<folder server-relative URL>