may i recommend you try and actually go observe an autopsy at either the hospital or your county medical examiner's facility? you'll get a much better understanding that way than to have someone explain it. for one, each autopsy is different because they're guided by clinical history. like living person medicine, your "differential" is guided by age, known medical conditions, the "history", and of course, the "physical exam". so a healthy 20 year old dropping dead is thought of much differently than a 66 year old man with a history of poorly controlled hypertension and dyslipidemia dropping dead.
contact your school's pathology course coordinator or department chair and simply ask to observe an autopsy - that's gonna be the best way to obtain the information you seem to want.
I get the sense already that this question comes up because you are afraid (in some sense, anyway, whether you think it's gross or frightening or evil or unnecessary or whatever) of autopsies. Autopsies are vital to the education of a pathology resident. You see things you will never see anywhere else, and you learn about connections and associations as well as how to do important things. They are mandatory for your education for a reason. Almost everyone gets used to them and is able to handle it very well, despite any preconceived notions about whether they will or not. To what extent they are important is debatable and depends on who you ask. Most of the time (but not always) you will be assisted by an autopsy diener who does some or a lot of the cutting and setup, cleanup, etc.
There are plenty of textbooks at libraries which relate to the exact procedure on how autopsies are done.
(edit not for you, but some premeds wander in from time to time)
Most medical schools still have gross anatomy with have cadavers.
However some wimpy schools have prosectors do all the work, and even worse there are some schools that don't have gross anatomy lab.
But the majority of medical schools do still have antomy lab.
Yaah's advice is good. Or atleast do some reading (and don't watch CSI)
I wasn't thrilled about the prospect of doing autopsies either, but like gross anatomy, you have about 3 seconds to think about how wrong/gross/foul it is and then you have to start performing. After a while, it just becomes another part of your job. Any thoughtful person is going to have reservations at first, so I wouldn't worry about it too much.