Cut the flooring boards to size using a circular saw.
How to install wood laminate flooring on stairs.
Apply flooring glue of the back of the boards and place them on the steps.
Laminate flooring installation on stairs.
Nail the boards into place with finishing nails.
However installing laminate flooring on your stairs is a completely different matter.
Alternatively you could cover the overhang with plywood to make it level.
To install laminate flooring on stairs start by removing the overhang or the underside of the stairs with a jigsaw.