I started up with Distance Learning systems and will be studying the A & P first. They sent me a 500 pg book. Any advise on how to study or what other material might I need.
Since you have that 500-page book, you might as well use it. Grab your free content outline from EC, go through that book, and highlight details based on what's in the outline. Not everything in that book will be on the test so you must use the outline as your map. As LunahRN said, the practice exams will help tremendously and they will give you some idea of what to expect on the exam as far as how the questions will be asked.
What I did was focus on the areas that did not carry a lot of weight, while trying to learn SOMETHING in all the areas. Other students focused on the areas that did carry the most weight. None of the information was sticking for me since I don't even come close to imitating a biology person but I landed a B on the exam.
So, just start by relaxing in the fact that you DON'T have to know that entire book, yet you don't know which 160 questions will be asked of you. The only way to narrow your study is by the Excelsior College content guide, which also comes with practice questions and rationales at the end of the guide.
Content guide! Content guide! Content guide! Don't waste your time studying information that is NOT on the content guide! Any ONE of the EC advisors will tell you that. Good luck on your exam!!