Place 2 stairs side by side for the seat
Add a row of slabs behind the stairs for the backrest
Use trapdoors on the sides as armrests
Put carpet on top of the stairs and slabs for a softer look
Use signs or fences behind the sofa if you want a taller back
Use different block colors to match your room
Make a corner sofa by extending the stairs and slabs in an L shape
Add buttons or pressure plates as small decorative details
Place the sofa against a wall for a more realistic look
Use banners or wool blocks nearby to match the sofa design