Start FILER and go to the C:\_DAT directory ( If needed, press [ESC] until C:\*.* is displayed in the top right corner of the screen. If you find yourself in the "Available Drives" screen, highlight [-C-] and press [ENTER]. Then highlight _DAT and press [Enter]).
Press the [MENU] Options keys and observe that the word "Filter" is the first option in the pull-down menu. Also note that the "hot-key" for this operation is [F4]. At this point you can press either F, [F4] or [ENTER] to open the "Filter" box. Type in *.wk1 and press [ENTER]. FILER will show only those files with a .WK1 extension. The "*" (asterisk) is called a "wildcard" because it can stand for any combination of letters and/or numbers.
If the list is empty, it means that there are no such files in this directory. The highlighter will be on the "View Up" line.
Press [ENTER] to return to the C:\ (root) directory.
If there are no files with *.WK1 in this directory the list will be empty and you'll be stuck.
To get back to the \_DAT directory you'll have to press the [F5] (Goto) function key and type _DAT in the Goto box and press [ENTER] or [F10].