Open a new mail message (the one that you wish to send), then click on the
To... button. Select "purple" and the name of the group (correctly called a
Distribution list) will appear.
If you are sending to a group of folks that don't know one another, I
suggest that you use the Bcc... button instead.
I take it the Purple group is a Category of Contacts. You will not be able
to access them in a DL as described in the previous answer. Do it this way:
Select all members of the Category (click the heading bar when they are
grouped By Category) then drag them to the Sent Items folder or right click
and select New Email Message.
All names will go into the To... field. You can show the BCC field and drag
them all there if you need to hide their addresses.
