well, most of the commands take parameters. so try entering, for example, "sin (* pi .5)" (without quotes). this returns the sine of pi divided by two (which is one).
if you have any questions about what parameters some of the functions take, let me know. i suppose i could have (and perhaps should have) written that information out where i listed them, but that would have taken a long time
in the final game everything will be documented of course.