The search menu
On the top right of the grid there are two buttons that respectively activate and deactivate record filtering. The former add a row of editable fields just below the column titles where you can insert values that will be used as a filter on the particular column. The latter clears all the current filters.
As shown in the figure, with the menu on the left you can select a different filtering criteria, for example to select players born before a particular date.
It is possible to search on one or more column at the same time, for example to show only french players you can enable the field guilabel:country and type the text FRA in its search field, then maybe typing players initials in the field firstname.