Place the cursor where the footnote is required and then either click "Insert" and select “New Footnote” from the drop-down menu or; right click and a pop-up panel appears; hover on "Insert"; again a new pop-up panel appears and how select the option "New Footnote".
If there are no footnotes in this article, a pop-up warning will appear:
Click the "OK" button and the Add/Edit Footnote box will pop up.
Paste or type the required text in the box and click the button "Add Footnote".
When the "New Footnote" is inserted (see the above image), the circled number represents the new footnote citation.
To delete or update a footnote, click on the respective footnote superscript, the above box appears. Click as required "Delete Footnote"/"Update Footnote".
You can amend any existing Footnote-Citation link by clicking the superscript number to open the pop-up menu, scroll to select the correct footnote (now highlighted in blue), and deselect the unwanted footnote by clicking it to toggle off the highlighted selection