Uh, yeah, it's a basic synth, but to say there's nothing that isn't obvious about it is just inaccurate. It's oscillator waveforms are not even identified. It's just a knob with 9 positions, none of which are identified. Maybe sophisticated synth users can hear the difference between a 6% Pulse Wave and a 12% Pulse Wave, but I doubt that most can do that just by rotating the dial...particularly if they are using Square instead of a more feature-rich synth.
Also hidden are certain knobs. For instance, I don't think it is "usual" that if you click on the "Shape" label that all the knobs become "Mode" knobs instead of Shape knobs. There are several situations like that. Fine becomes Phase. Coarse becomes Pitch EG. Etc. Right clicking the Square I label in the bottom corner generates random patches.
The best thing to do is get the user manual for Pentagon I, which is a synth that Cakewalk sells (but you can find the manual without buying the synth). Square I is just a light version of Pentagon, so a lot of what is in the Pentagon manual will help you with Square I. I'm 5 1/2 years too late to help the original poster, but maybe someone else will find this on Google.