jigsaws normally cut on the upstroke so cutting the counter top from
the bottom side is the best way to go. When you are cutting the
opening for the sink drill the corners as suggested and make sure you
support the piece to be cutout or it can split the laminate. I usually
cut two opposite sides then screw a long board across so when I finish
the cut the piece won't fall. You should also use masking tape to help
protect the laminate from chipping.