If you want to connect your desktop Word application to your EndNote Web library instead of your EndNote Desktop library, follow these steps. Note, you must have EndNote Desktop installed on your computer first. (PC installation, Mac installation):
Open a Word Document and select the EndNote tab on the ribbon.
Select the "Preferences" button on the EndNote ribbon (under the Tools section):
This will open a pop-up window. In the pop-up window, select the "Application" tab.
Select "EndNote online" from the dropdown menu next to "Application"
Here you can confirm your EndNote online credentials, and when you select "OK" it will then connect to your EndNote Web library.