All directories have a slash '/' at the end of the directory name and
they are displayed at the top.
Double click on a directory to display its contents. The two top directories are special :
'../' stands for the parents directory - it goes up the tree and './' stands for the current directory, so you can reload the current directory.
Below the directories are the files in the current directory. To select one, either click on the name, and the name is marked in inverse colours. To choose this file and leave the file chooser, either click on the name again or on the [ OK ] button.
The [Cancel] button will leave the file chooser without making a selection.
Both the directory and the filename can be typed manually. The text entry fields become active if you click on them.
Hit RETURN in the "File" entry field and it acts like a a click on [ OK]
with this file selected.
Hit RETURN in the "Directory" entry field and it displays the contents of this directory.