How to use UI Framework in Winforms C#?

Question

How to use UI Framework in Winforms C# i am using bunifu VScrollbar but i need to use it in flowlayout Panel but it is hard to use it because it is overlappinng on my only one panel in which 3 buttons are dock and all panel in flowlayout panel is dock and vScrollbar of bunifu is only fit  on last panel or button Please help me how to resolved it and also help me after setting of Vscrollbar how to use it on flowlayout Panel to Scroll It?