To send a campaign at a specific date and time, you use the Standard campaign type. The date and time of sending is set on the Campaign Summary screen (the fourth step of the campaign creation process).
Scheduling a campaign:
Navigate to the Campaign Overview screen by clicking “Campaigns” in the top menu.
Click “New Campaign.”
Select the “Standard” campaign type by clicking it (it should be selected by default).
Click “Next” in the top-right corner of the screen.
Select the list you will send to. Click “Next.”
Choose a template for your campaign.
Design your campaign. When you are finished, click “Next.”
You should be on the Campaign Summary screen. About halfway down the page you’ll see a section labeled “Delivery.”
Click the “Schedule” button. A date and time field will appear. Clicking the down arrow on the date field will bring up options to send Tomorrow, Next Week, Next Month, and Specific Date.
Click “Specific Date” and use the calendar to set the date you want to send by clicking it. The date you select will populate the date field.
Click the hour and minute to set the time your campaign will send. Note the time zone that appears to the right of the time as this is the time zone being used to schedule the campaign.
Clicking Finish will schedule your campaign. You'll be directed to a confirmation screen and your scheduled campaign will appear in the left hand sidebar of the Campaigns Overview screen.