To install laminate flooring on stairs start by removing the overhang or the underside of the stairs with a jigsaw.
Installing laminate on stair stringers.
The risers go on next.
Alternatively you could cover the overhang with plywood to make it level.
However installing laminate flooring on your stairs is a completely different matter.
You have to ensure that there are no gaps and spaces in the flooring and it is complete and perfect in every way.
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 install laminate flooring on open stairs.
Laminate flooring installation on stairs.
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.