That's it, you're on your own now.
For the most part, you can easily translate the documentation given
for Perl/Tk to Ruby. But there are a few exceptions; some methods are
not implemented, and there is undocumented extra functionality. Until a
Ruby/Tk book comes out, your best bet is to ask on the newsgroup or
read the source code.
But in general, it's pretty easy to see what's going on. Remember
that options may be given as a hash, or in code block style, and the
scope of the code block is within the
being used, not
your class instance.