To filter contacts go to Contacts > Filters.
To create new filter press “+ADD NEW” button. Enter filter name and select options you want to imply on that filter and press “Apply”. Filter will be created and applied.
Use equal and non-equal (" = ") comparison option for more precise results.
To clear filter, simply click on “X” in ribbon above contacts.
Once you apply a filter, you will be able to use it in future as well just by clicking on it from the Filter list. You can share filter with other users in your org by ticking Share filter or you can leave them only for yourself.
To delete a filter from the list, tick the checkbox next to the filter you want to delete > Actions > Delete