keynote

I've decided to escape from powerpoint but I've found one killer problem
with keynote. It will not let me decide when I want to advance to the
next slide but, using the play option, insists on playing it. So how do
I do a full screen presentation advancing to the next slide by hitting
the space bar like I'm used to (using powerpoint on a G4 powerbook).
Help is less than helpful.

Pete H