To add a web browser favicon:

After you login, look on the left side for the word ‘Media’

Upload your .PNG file that has been sized for a Web Browser Favicon dimensions (32 x 32 pixels)

In the ‘Media’ library click on the file you just uploaded

On the Right, look for ‘File URL’ and click ‘Copy URL’

On the left click the ‘Customize” link found on the left, under ‘Appearance’ > ‘Customize’

Then Click ‘Site Icons’ on the left

Paste the URL you copied into the box labeled ‘Favicon (Set Path to Image Below)’

Click Publish at the top