Is this assignment referring to the Kings of Judah and Israel as recorded in the Bible? If so, then this is a large assignment. This is not one I can, or should, simply give you. I can give you some advice on how to proceed.
First, list the Kings. For clarity, you may want to have three separate lists.
The first list of Kings will be from when the Kingdom was united. The second and third lists will be from when the Kingdom was divided; one list for Judah's Kings (the Southern Kingdom); and the other list for Israel's Kings (the Northern Kingdom).
Lists of Kings
1. United Kingdom
2. Judah (Southern Kingdom)
3. Israel (Northern Kingdom)
Start with Saul, David, Solomon, then keep going. The Kings are all there, listed in the Bible in the books of I & II Samuel; I & II Chronicles; and I & II Kings.
Then, read about each King. As you read, find what looks like each King's actions that helped to preserve the Jewish Religion and Way of Life; and write it down by each King's name. Unless you have a *textbook that has already spelled out these contributions, you will have to glean or infer from the text what each King did that was significant to keeping his people unique in the world.
*I don't know the specifics of this assignment. Do they want you to use other sources besides your textbook? Or do they simply want to see if you are understanding what you are reading?
Finally, rewrite and summarize what you found, making it concise and presentable. Do they simply want a list? Or do they want complete sentences?
Something to keep in mind: Does your assignment require source citations? If so, make good notes of where you get each piece of information.
I hope you do well on this. This is a very interesting subject.