That is exactly why we tell you not to study anatomy prior to starting med school. WAIT til you start the class.
In the class, you will be introduced to it bit by bit, and as you do the dissections, section by section, it will make sense.
Once you are in the class, I highly recommend using drawings as a study tool. Example..be able to draw the brachial plexus, and then extend each nerve all the way down, noting not only the muscles that each innervates, but the structures that it passes by as landmarks (eg it may go under a particular blood vessel). The relationships of the structures to one another are very important, especially for exam purposes. Exam questions tend to ask things like.. a person sustains an injury to a particular area, which structure is most likely to be injured? Also, for the lab practicals, you'll identify the structure much more easily by noting the landmarks around it and it's relationships to them rather than just try to recognize it.
Again...DON'T TRY TO STUDY for med school now. PUT NETTER AWAY. Nearly every course in medical school is overwhelming when you look at the sheer volume. Wait til you get there and it is broken down for you. Otherwise you will get yourself all psyched out (as you have already). Anything you learn over the summer will only be a very small tidbit compared to what you will learn once you start.
You will wind up developing your skills in absorbing an amazing amount of material in a very short period of time.
So RELAX for now. Med school is stressful enough. Don't start stressing now.