Go to your Settings (1), then go to the Email tab (2) and click on Gmail (3):
In the field that appears, leave or change the email address you want to connect to send your emails (1), then click on Connect (2):
You will be directed to a new webpage to allow Datananas to access your Gmail / G Suite account (1 & 2). Then click on Continue (3):
You will be redirected back to Datananas, your email address is now synchronized. A message in green should appear to confirm:
After connecting your Gsuite email address, your hourly and daily send quotas will be automatically updated. You can change them at any time (see how to do it).