LMB = left mouse button
MMB = middle mouse button
RMB = right mouse button

- Select files with LMB and/or MMB. You'll figure out what the
  difference is. (You can also use LMB+Ctrl to do the same as MMB).

- When you have selected something, you can press one of the middle
  command buttons (in the window) with the LMB to do stuff. 
  If you press the command buttons with the RMB, the command will 
  execute in the background.

- View things with RMB or double-click LMB.

- Enter directories the way you view things (see above). Try pressing the 
  Ctrl-LMB when you enter directories.

- Type an FTP URL in the directory entry to browse an FTP site.

- Try "Configuration->Edit Configuration" to edit lots of
  configuration options.

- After adding stuff to the hotlist, do "Configuration->Save
  Configuration" to save the hotlist for later.

Mouse operation summary:

LMB         - select/unselect (clears selection first)
MMB         - select/unselect (does not clear selection first)
Ctrl-LMB    - select/unselect (does not clear selection first)
RMB         - view things/cd to directory
Double-LMB  - view things/cd to directory
Ctrl-RMB    - View directories in opposite panel