TBIDesigners

Hello! I am trying to create a custom railing for my staircase but I cant seem to figure out how to turn it from a cap and rail to just a custom railing on the stair treads themselves. I want to enclose the staircase and with a wall but "closed underneath" doesn't work because it is a 3 story stairwell I am trying to create. below is what I have when creating a custom railing and the second photo is how I want that custom railing to finish on the stairs?? Any advice???