How do you check the lower unit oil on a 25 hp Johnson?

there should be two flat head screw plugs in the side down near the prop. there a low plug and a hi plug. U want to fil it up until it come outs the hi plug. use the low plug to drain it as well as fill it. yes its best to fill from the low plug they sell little hand pumps the fit on the gear oil bottle. while ur ein there its best to just change the oil. freash oil never gonna hurt anything. just pump in gear oil from the low whl eontill it starts coming out the top plug, with te motor down as if it was it water trimmed and level