Applying to the Chemistry Department

I was wondering if anyone out there has had any experiance in this? Im a little confused on the dates. It says the application is due the second week of October or April. Since April has already passed by then the next time I can apply is in October. Would that, if accepted, put me in the department for winter and spring quarter? What do I do in the meantime? Do I take classes that go toward the chemistry major such as math and physics? Any help is greatly appreciated.