The risers go on next.
How to finish stairs with laminate flooring.
Cut a piece of laminate flooring for each tread.
Laminate floor planks work well on stairs.
Alternatively you could cover the overhang with plywood to make it level.
The international building code specifies a maximum riser height of 7 inches so a single laminate plank usually suffices but you may prefer to use pine poplar or some other stainable wood instead.
To install laminate flooring on stairs start by removing the overhang or the underside of the stairs with a jigsaw.
The riser must come flush with the surface of the tread and the stair nose which goes on last curls around the top of the riser and either fits flush against the laminate.
How to finish stairs with laminate.