First check your engine oil level and ensure it is OK. Remove the plastic shields under the engine so you can access where your oil leak is from. Replacing the engine oil pan is a bigger job than most people would want to tackle at home. The engine needs to be supported, the exhaust needs to be removed, (sometimes these bolts are rusted and break on removal), the lower cross member gets removed all in all about three and a half or four hour job. If replacing the oil pan ensure the engine oil pick up tube is not damaged.