Is this True Antislavery groups in Kansas have their own elections and adopted a constitution that banned slavery?

Yes, it is true that antislavery groups in Kansas held their own elections and adopted a constitution that prohibited slavery. This was part of the broader conflict known as "Bleeding Kansas" in the 1850s, where pro-slavery and antislavery factions clashed over the status of slavery in the new territories. The Free-State movement aimed to establish Kansas as a free state, leading to significant political and social turmoil in the region.