An explanation of how to use the Dasher panel is here.
Dasher for Mac OS X enters its text directly into another target application, which you can choose from the dropdown box in the Dasher window or, if you uncheck "Lock", will follow the normal input focus. Alternatively/additionally, you can copy the text you write to the clipboard and/or have it spoken aloud (see inPreferences window).
There are a number of preferences you can adjust on the Dasher Preferences Panel (Dasher->Preferences...).
If you wish to use a non-English alphabet, you may want to pick up a training file for your chosen language. There are a number of training files on the website. Once you've downloaded a training file, you should put it in your own Library/Application Support/Dasher folder (if any of the folders in the path don't exist, just create them).
Please visit our website for more information on Dasher.
We'd appreciate any feedback / bug reports / patches - please send them to dasher@mrao.cam.ac.uk
Yours,
The Dasher Team