Take your old pads off, then use steel wool or a similar-type material and thoroughly go over both sides of your brake discs where the pads make contact to remove any residual material from the old pads. Clean the caliper and sides of the brake pistons with some brake cleaner and an old toothbrush, then install the new pads (you can also put a tiny dab of copper grease on the sides of the brake pistons to lubricate them, but be very careful not to get it anywhere else).
Once the new pads are installed ride a couple of hundred yards back and forth and moderately apply brake pressure. I would recommend doing this 5-10 times. Then use your first track session with the new pads to scrub them in through progressively harder braking.
Good luck.