The only way to do that is to take your Seymour ancestors back one generation at a time back to the 1500s. There's no guarantee that they are connected to Lady Jane Seymour. It could be just a family story. Or you could get lucky and connect to an existing line. Here's one step. The earliest Seymour in your tree is Charles Dwight Seymour, born 1863 in Hadley Mass. https://www.wikitree.com/wiki/Seymour-6474 There's a Charles D. Seymour in the 1880 census. Born 1863, living in Hadley, Mass, the son of Edwin H. Seymour (age 54, born 1826 in Mass.) and Julia D. Seymour. https://www.familysearch.org/ark:/61903/1:1:MH6G-VXZ But there's still a long way to go.