Here you can set the sender name and email as well as the reply to that the receivers will see in their mail client. The reply to data will be used by mail clients if they reply to your campaign.
You can also add some email addresses as BCC (Blind Copy Carbon) if you want to send a copy of the campaign to specific email addresses. BCC addresses can't be seen by other receivers.
You can choose to send you campaign as soon as you confirm it in the next step or at a specific date. If you want to schedule the sending, a new option will be displayed to let you choose the sending date. Click on it to open a time picker.
A more complete description of the automatic option can be found here.