Q. Is the Book of Mormon supposed to be the first book made? I thought the Bible was the only book. Where did the book of Mormon in the Bible come from?
The Book of Mormon is actually not one of the books of the Bible. The biblical books of the Old Testament come from several to many centuries before Jesus, while the New Testament books were written within the first century after Jesus. The existence of these books in these time periods is attested by ancient translations, quotations, and copies. (There is some debate among scholars about the exacting dating of specific books, but I think this is a fair summary of the general consensus.)
The Book of Mormon, for its part, first appeared in the year 1830. It was published by Joseph Smith, the founder of the Mormon Church. He said that the book was a translation of writings that were engraved on buried golden plates that an angel told him where to find. These writings, he said, came from prophets who lived on the American continent up to four thousand years ago. But Smith never produced the plates, no other copies of them are known, and no evidence of these prophets, their lives, or their words is found anywhere else. It’s a matter of faith for Mormons that Smith’s account is true, but others have questioned it because of this lack of evidence.
What we can say is that the Book of Mormon is the oldest of the books that Mormons consider sacred. But it comes from a much later time period than the books of the Bible, which Christians consider to be inspired and authoritative.
Good Question 
Your answer to the question about the Book of Mormon is respectful and mostly accurate. It is important to note that church doctrine includes the Bible to be the word of God and is the oldest scripture that we hold as sacred. In fact, the Book of Mormon prophets often quote from Isaiah, and speak of Moses as a type for Christ.