Create a mail merge using Gmail and Google Sheets

Need to customise Googlsheet to send Emails from My Gmail Draft .
Set Timer to Auto Run on a Daily, Weekly & Monthly
Auto trigger to send email when Row are completed
Include unsubcription List

See sample of sheet on gsuite link below.
https://developers.google.com/gsuite/solutions/mail-merge

Understand Java Script, Googlesheet, Formula’s, Python