At this point, the Kepler - Attachment fields | simple & multiple custom field is ready to be used as follows:
Step 1: Click on Attach file Icon 
to select a file.
Step 2: Choose a File from the opening window.
Step 3: As depicted in the screenshot below, some information about the uploaded file is available:
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PS: When users attemp to attach empty files to an issue an "Empty File Warning" appears, the attachment process is not blocked so users can proceed as needed.
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