Hi @mike1,
Unfortunately, it will not be possible to see the files in the Box.com dashboard because the files you uploaded via plugin are in your Service cloud (which is only possible to access via plugin because it is a service account).
The files that you see in your Box.com dashboard are from your own Box account.
However, if you have a paid Box account, you can try the Content Manager in order to access the dashboard UI.
Best,
Alex