Using this oil change kit is a breeze. First, make sure your engine is cool. Then, locate the oil drain plug under your car and place a drain pan beneath it. Remove the drain plug and let the old oil drain completely. Replace the old oil drain plug gasket with the new one provided in the kit and reinstall the drain plug. Next, find the oil filter and use an oil filter wrench to remove it. Apply a bit of new oil to the rubber gasket of the new K&N oil filter and install it. Finally, pour the Motul synthetic engine oil into the engine through the oil filler cap. Make sure to check the oil level using the dipstick. As for maintenance, keep an eye on your oil level regularly. If you notice any leaks or strange noises from the engine, it's a good idea to check the oil filter and drain plug. Also, follow your Subaru's recommended oil change intervals to keep your engine running smoothly.