Creating a new message is as simple as clicking the New Email button from within the "Home" tab.
Keyboard shortcut To create an email message, press Command(⌘) + N
To select recipients' names from a list in the Address Book, click the address book icon located next to the To, Cc, or Bcc fields, and then search for and select the names that you want to include.
Important: When using the search feature, select "your name Directory" to search against UW-Madison's Office 365 directory. We also recommend that you select "Search all fields" option to get a better match.
Note: To display the Bcc box for this and all future messages, click Options, and then in the Show Fields group, click Bcc.
After you have composed the message, from within the "Message" tab click Send.