The L298 is a dual bridge. It does not have the logic for step and direction input. It would take some logic ICs to generate that. And far more logic to generate microstepping for smooth motion at a fraction of the pulse frequency. Using a 1/16 microstep controller and (say) a 1.8° stepper, you'll get 3200 pulses per revolution, so 100 RPM would be about 5kHz.
If you replace the L298 board with a stepper driver board appropriate for your stepper motor you can simply connect them (small steppers for 3D printers and such like often use cheap modules such as those based on the A4988 chip). There are metal-cased modules suitable for larger steppers. They all will accept step and direction and generally have some adjustment for coil current (and can accept higher voltages- up to 12, 24 or even 48V - in order to better control a low-voltage stepper. I don't know if your pulse/direction generator frequencies are appropriate for a "Baby bed Carousel" or whether the resulting angular velocities would be more at home in a trebuchet emulator, but that's another question.
The L298 is a ancient and fundamentally evil part that wastes more power than it supplies to the motor at low voltages. I suppose it was the best they could do in the 1970s.
