The previous comments of the reviewers' and editors' can be found under "Editor/Author Email Record".
After uploading the revised manuscript, click the "Notify Editor" icon.
In your response, please number your responses, quoting the original peer-reviewers' / editors' comment, and then describe on how you responded to the comment.
After sending your notification email, your responses will be visible in "Editor/Author Email Record". Here you will also find a log of any future communication, including further revision requests, acceptance or rejection notices etc. (these will also be sent via email).
Under no circumstances should a direct email be sent to the editor, bypassing the manuscript management interface. Such emails are considered off-the-record, and will NOT be logged (unless the editor adds it to the log).