Hi Alison,
Just click the header bar that says "Received." That will sort your mail by
date. Click it again to reverse which items are on top (older vs. newer).
Clicking "Subject" will sort items by what you have in the subject field. It
won't look the same as Gmail, but each individual email will have a record of
all previous conversations in that email chain embedded in the body of the
email.
If you do not see the "Received" title in your header bar, right-click on
the header bar, and select "Field Chooser." Click and drag "Received" onto
your header bar to the location you'd like it to appear. Then you should be
good to go.
