> I am desperately looking for a documentation.M-x find-library RET ox-freemind RET
Just look at English strings there. That should give you a pretty good
idea of what you can do.
You can also search for the string - left or right - and you know that
the exporter already has some trick up it's sleeve.
Unless you give an example, it is difficult for me to understand what
> I want to position nodes on the left, for example, but I don't know
> how to pass optional parameters to the converter.
you want to achieve. How does your Org file look like and what node you
want to position left.