Go to the EndNote web site:
Register and Log in:
This step assumes you have already found and exported citations into EndNote Basic.
See the page "Getting Citations into EndNote" if you have not done this.
Let's put these references in a new group "COVID."
Click the tab "Organize" and select "Manage My Groups" in the drop down:
Click "Create New Group":
EndNote Confirms Your New Group:
Select the citations you want to move to a group.
Go to "Format" in the ribbon above your references.
Enter data in the drop down boxes that open.
This is what "Save" provides: