Using OneDrive with Windows 10 - not working

Dell Inspiron 15 series 3000 OS Windows 10 (upgraded from Windows 8.1)
On taskbar right-hand side there is an upward arrow. When I click on this a menu-box opens with icons for 'bluetooth', 'touchpad properties', my anti-virus program, 'intel graphics 'and 'OneDrive'.
 1. I notice the OneDrive icon is not in the blue colour which it showed in  the identical menu-box in Windows 8.1.
 2. When I right- click on the OneDrive icon a menu opens:  the top option is: 'Open your OneDrive Folder'. This is greyed out and when I click on it nothing happens. Another option is 'Go to OneDrive.com', but this is also greyed out and will not open. The same with the option 'View sync problems'. The only options which work are 'help' , 'settings' and 'exit'.
3. I have copied files to the OneDrive folder in the 'File Explorer' window. But when I go to my browser and open OneDrive there (on the internet)  the files I have copied do not appear. The only files which appear are those which I entered into the  cloud OneDrive Folder when I was running Windows 8.1

I need to get OneDrive working. Any help appreciated