When writing a biographical paper you usually need to cover:

Background of the person

What was going on during the time period in the country that they lived

What they are known for and what accomplishments they made to the world.

Begin with an encyclopedia article like Wikipedia to get background information …be careful with wikipedia because all information is not always correct.

The next step is to look for more information in books, using school provided databases. I usually recommend not using Google to my students because they have trouble reviewing the sites to pick one that is beneficial to their searches.

In googling "Ghengis Kahn", I happened to find a web bibliography for Ghengis Kahn - you are very lucky…

Now in my personal opinion as a Teacher - Librarian, shame on the teacher who does not give you a handout with their expectations for the paper and a rubric.

How long should it be? etc are the things you may want to ask…your parents can ask for a rubric so they can see how you will be graded. If you feel that the teacher would be open to you, you could ask but coming from your parents it may be safer for you.

G

Realm of Mongols:
What happened after 1206 is reasonably well understood at the academic/rational level. The invincible Mongolian hordes, under the leadership and tutelary power of Chingis Khan, overran most of the Asian and Eurasian land, and in their heyday, the Mongols never met an army they could not beat. They were incomparably superior, man for man, to what their formidable military opponents in China, Russia, Persia and Western Europe could muster. Their dedication, sense of purpose and endurance is simply matchless in human history, past and present. Most remarkable of all was the degree of solidarity and feeling of shared purpose that the Mongols evinced up to the death of their beloved leader in August 1227.

From Wikipedia: Genghis Khan (pronounced /?d?????s ?k??n/ or /??????s ?k??n/[1]; Mongolian: ?????? ???, Chinggis Khaan, or ?inggis Qa?an), IPA: [t?i???s ?a??]( listen); c. 1162[2]–1227), born Temüjin (help·info) (meaning "ironworker"[3]), was the founder, Khan (ruler) and Khagan (emperor) of the Mongol Empire, the largest contiguous empire in history.

He came to power by uniting many of the nomadic tribes of northeast Asia. After founding the Mongol Empire and being proclaimed "Genghis Khan", he started the Mongol invasions and raids of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. During his life, the Mongol Empire eventually occupied a substantial portion of Central Asia and China.

Before Genghis Khan died, he assigned Ögedei Khan as his successor and split his empire into khanates among his sons and grandsons. He died in 1227 after defeating the Tanguts. He was buried in an unmarked grave somewhere in Mongolia at a location unknown. His descendants went on to stretch the Mongol Empire across most of Eurasia by conquering and/or creating vassal states out of all of modern-day China, Korea, the Caucasus, Central Asian countries, and substantial portions of modern Eastern Europe and the Middle East.

Check those links below, there's a lot more information in 'em. Or just drop his name into the Google box, why don't you?