From the Start screen, swipe left to display the apps list.
Alternatively, tap All apps (located in the lower-right; may require scrolling to the bottom).
Tap the email account (e.g., Outlook Mail, Google Mail, Hotmail, etc.).
Tap new (located at the bottom).
From the "To" field, enter an email address or contact name.
As you enter the address or name, potential contacts are shown. Tap a contact or tap Search Directory for a complete list of contacts to choose from.
Repeat this step as necessary to add additional recipients.
From the "message" field, enter the message.
Tap the Attach icon (located in the middle above the keyboard) to add an attachment.
Tap the More icon for other options (e.g., Cc/Bcc, Insert, Options, etc.).