Germinal, an adjective, describes something that is just starting to happen, like all the planning you did and people you got interested in joining the running club when it was just an idea. That's the germinal stage.
To correctly pronounce germinal, accent the first syllable: "JER-mih-nul." You can see and hear germ in germinal. It comes from the Latin word germen, or "sprout, bud, sprig, offshoot." So, something in its germinal stage is just beginning, like when you are thinking about possible topics for the research report you are going to write.