It all depends on your dopus setup. Not sure how the default lha button works, try having the directory with your lha in your source window and the destination where you want it in your destination window. Perhaps it works like that.
I'm not a dopus user nor do I know what WB distribution or whatever you're running.
What I'd do: open a shell and type lha x path:to/packetname.lha ram: and see the files extracted to ram:
Don't give up. There's some learning to do, but in the end you'll know how to use an Amiga. :-) Lots of books on the subject at
www.bombjack.org's commodore section.