How do i place Select Boxes under Options

How do i place select boxes under options in products, like if i place 3 options , 1) fabric only 2) stitched fabric 3) customize your size, when someone choose option 2 there will appear 2 select boxes to select 2 different sub options, how can i do it? any help???

@Qphoria thanks for your help but i want to place select boxes under radio button options like utsavfashion.com