Filtering emails

In apple mail I can no longer filter emails in my inbox other than by 'unread'. I got a new mac for Christmas, but can't see how that would make any difference? There used to be a 'filter by' option and then I could choose 'flag' 'unread' 'date' etc ...... now, all I have is the filter symbol and the only option seems to be 'unread'.

Any ideas ?

Thanks.

Shona