What are some of their major achievements and major leaders in Song Dynasty?

The technology developed rapidly during that period. A lot of tools and weapons, like, compass, movable-type printing, cannon, and musket, were invented at that time.
Major emperors: Song Taizu (Zhao Kuangyin), Song Taizong (Zhao Guangyi), Song Zhenzong (Zhao Heng)...
In addition, I found many other information about this dynasty on this page. It's worth to read it.