Take off the lower splash shield which is under the front bumper. You may need a large torx screwdriver or socket.
In the lower passenger corner look for a slotted or cross-slotted plastic plug. You can work a medium long screwdriver in to loosen. It has a retainer, so it doesnt fly out. Have a LARGE pan under the car, and close to the tire. The coolant will splash all over. When done, screw the plug back in snug. It will feel a little "springy", so don't over-tighten. Check for leaks after refill, and tighten more if needed. Good luck.
Al