The first event leading up to Bleeding Kansas was The Compromise of 1850. This was a package of 5 bills passed by U.S congress, which sparked confrontation between slave and free states.
One of the bills passed was The Fugitive Slave Act. This allowed fugitive slaves to be entitled to a trial by jury, despite the 6th amendment.
Harriet Tubman was a previous slave, who escaped to the North when her owner passed away. She began to help lead slaves to freedom using the "Underground Railroad" this enraged slave owners and southerners.
Due to Popular Sovereignty, Douglas introduced a bill to divide the area into two separate areas, Nebraska in the North, and Kansas in the South. This started the race for possession of Kansas between the North and South.
Antislavery settlers in Kansas founded a town called "Lawrence". This town was condemned by the Pro-slavery Jury. They saw them as traitors and began to arrest the townspeople, burn buildings and steal items from homes and stores.
John Brown was an abolitionist who led a group to a Pro-slavery house, where they stabbed and cut the hands off of 5 men. This led to other incidents and ended up giving Kansas the infamous name, "Bleeding Kansas".