Hello @Hilary-Stoupa,
When I create a new form using "InfoPath Designer 2013 > New > SharePoint List" and add files using File Attachment, I can attach multiple files one under the other.
When I create a new form using "InfoPath Designer 2013 > New > Blank Form" and want to add a file using File Attachment, I cannot add more than one file, I can only add one file at a time.
Sample files are attached. Can you help me to add multiple files with blank form?