To set up who your email will be sent to, use the Data tab to select Recipient Lists and Segmentation.

Use the buttons at the top of the page to select Include and Suppression Lists as well as Segments.

As the lists at the top are changed the section at the bottom will update to show a preview of the recipients who will be included in the send.

Calculating the list using the Calculate option on the right will provide a full send list which can be scrolled.