Yeah, Sporcle's not the best interface. You're very limited as to the directions you can give. VAX would probably stroke out at how inefficient they're layout is.
DIRECTIONS: You guess random words (start with common ones) and they'll show up. The more you get right, the more you'll likely recognize the song. Once you realize what song it is, you have to remember all the lyrics and type them in before the timer runs out.
Here's a great example.
http://www.sporcle.com/games/fiendishthingy88/gbl122109
I'll give some hints to show how it works. This is a Beatles song. Begin with these words:
I
you
at
the
it
and
be
we
with
love