If needed, log in to Dropbox using your credentials (email & password).
Select Create App.
Select Scoped Access and choose the Full Dropbox access type.
Enter a unique name for your app and create the app.
Retrieve the app key and the app secret. You should also provide the redirect URIs accordingly.
An example can be: https://cloud.trados.com/<tenantId>/api/v1/content/oauth/DropboxContentProvider. The <tenantId> part of the URL is the Trados account ID.