The author note is treated differently than a regular footnote. It is not numbered or referenced in the text. It is typed on a separate page, or if the paper is blind reviewed (i.e., the reviewers for the journal do not know the identity of the authors of the paper), it is typed on the bottom of the title page. The author note will include departmental affiliation if it has changed since the study was run, information on the funding source or purpose of the study (e.g., dissertation), and where someone can write for more information (usually an email address).
Footnotes are referenced in the text with sequential superscripted Arabic numerals (e.g., 1, 2, 3, etc). The notes themselves are included on a separate page at the end of the manuscript.
Although footnotes can be valuable, it is best to avoid using them when their content can be worked into the text without disrupting the flow.