Knowing what the Torah is can someone explain what ...

The Talmud is referred to as an ocean because of its vast content. Judaism is based on law. The torah (Five Books of Moses) contains the basic laws given by God to Moses. Since these were basic laws they were not intended to cover all aspects of life. The Rabbis using 13 principle of study that were applied to the Torah text were able to come up with a compendium of laws that were a great deal more comprehensive. This vast work is called the Talmud. You would be best to consult the Jewish Encyclopedia for more detailed information.  

The Torah is the written law, the Jewish Bible, which was dictated to Moses on Mt. Sinai, and is believed to be the actual word of G-d.  In addition to the words that G-d wanted Moses to write down, G-d also explained details to Moses about what the words in the Torah meant.  For example, the Torah says that the Jewish people should observe the Sabbath and keepit Holy.  But, what does this mean?  G-d explained to Moses the answers to questions like this.  Then Moses was instructed to pass this information along to the Elders (the wise men in the Jewish community).   Then, these men went on to teach the children and the Jewish people.  This oral tradition is was passed on, generation to generation.  Then Rabbi Yehuda Hanasi decided that these stories and explanations really needed to be written down, so that they would not be altered and so they would be remembered.  The Oral Law was finally recorded in what is called the Mishna.  Rabbis from everywhere would study the Mishna, and these Rabbis would have very high-level discussions.  The discussions were recorded and compiled in what is known today as the Talmud.  Today, Jews around the world study the Talmud and hold the laws in the Talmud (the Oral Law) as just as important as the Torah itself.  It says in the Torah that the Oral Law should be taken as seriously as the Torah itself.  I have just given you the most simple explanation of what the Talmud is and where it came from.  Here is a more detailed

The torah contains the written law, while the Talmud is the oral law. According to Orthodox Jewish belief, the Oral law was passed down from Moses at Sinai, and then complied in the mishna. The Gemara involved the Rabbis arguing in order to understand the Mishna. The talmud is composed of these two works, and this is the basis of laws that we follow today.

When Mosses ascended Mt. Sinai he was given 2 Torah's the written and Oral.  The Written is what is comonly refereed to as Torah,  and the oral which explained the written and was foridden to be written down but carried equal weight as the written.  However as time passed explanations were forgotten and questions were posed to the Rabbi's decided it was better to violate the prohibition of writing it down than to forget it.  This is referedto as the Mishna and was broken in to 6 main categories and covered virtually every aspect of Jewish Life.  As time whent on the Mishna was starting to become a bit confusing and therefore questions arose and the great Rabbi's debated the questions and proved their opinions through incredibly complex logic this is the Talmud questions and answers on the Mishna