https://www.mozilla.org/en-US/thunderbird/features/ has a good overview and some screen shots. Columns in the mailbox views can be chosen from a list: Thread, Starred, Attachment, Subject, Read, From, Recipient, Junk, Received, Date, Status, Tag, Size, Account, Priority, Unread, Total, Location, and Order received. Of course, you would probably not choose all of those because of the available space on your screen. Subject, From, and Date (which includes time) are the most important to me. A separate pane on the left shows your email accounts and folders belonging to them (e.g. Inbox, Starred, Junk, etc.). Clicking on a folder displays the messages in that folder.