Never in a millon years would I ever use laminite flooring on a set of stairs.
#1 It has to have room to expand and contract. (there's a reason why they call it floating flooring)
#2 How are you going to finish off the edges.
#3 It's to slippery.
Armstrong came out with a stair kit long ago with a nose piece to cover up the ends of the flooring. The trouble is the nosing was just a peel and stick covering and there was a 90 deg. under cut which over time breaks off.
Use something like this instead.
Stair Treads & Risers