The oil filter is located in the engine compartment, it needs to be changed while on a lift as you cannot access it any other way. Once the car is on the lift, you should be able to spot the oil pan and locate the oil filter. Also, the oil pan may be hidden by a plastic shield... At any rate, changing your oil and filter is not a repair for anyone who does not have access to a car lift. Refer to your owner's manual to see which oil it uses and I would recommend taking the car to a lexus dealer or any oil change garage.