How do you use laser on Nerf gun?

If you mean the tactical light/reddot then you can adust the light spread with the slider on both sides, or switch it on or off with the switch. This then will show you with a rough guide where the bullet will strike, or show you surroundings dependant on which mode you use. with the recon, the laser is more accurate when placed on the barrel extensions lower rail, instead of the standard top configure.