What conditions that must be right for germination to occur?

It varies somewhat, but seeds generally need a warm moist substrate. So if you sprinkle some radish seeds onto a moist paper towel, put it into a ziplock, and keep it in a warm place, germination is likely to occur. Other seeds have different requirement though-- some seeds need to be partially digested by a bird or mammal before they can sprout. Weird huh?