Using this Subaru engine oil maintenance kit is easy. First, make sure your engine is cool. Drain the old oil from your Subaru's engine by removing the drain plug and placing the drain pan underneath. Replace the old drain plug gasket with the new one from the kit to prevent leaks. Then, remove the old oil filter and install the new K&N oil filter. Pour in the Motul 5W30 synthetic engine oil from the 5L bottle. After that, start your engine briefly to circulate the new oil, then check the oil level. Make sure to follow your Subaru's owner manual for the correct oil level. As for maintenance, it's a good idea to change your oil regularly using this kit according to your vehicle's recommended schedule. Always store the unused parts in a cool, dry place. If you notice any oil leaks after using the kit, check the drain plug and oil filter for proper installation.