Make sure the engine is not hot first, before changing oil. Lay some newspapers underneath your car, or some cardboard. So you don't get oil all over your drive way and leave a big mess.
Get some old shoes, shirt and a hat. You're definitely going to get a bit messy here. So no good clothes at all, or you'll regret this.
Make sure you have everything, like a ratchet, oil filter wrench, new oil filter, new oil. Check my things to need list.
Get a car floor jack. Make sure you're on a flat surface, before jacking up your car. For some big trucks, you might not need one. Most vehicles you probably will. This is a very important safety step. Click on my link below, for info on how to use one. Always test to see the vehicle is secure, before going underneath.
Get underneath your vehicle, find the oil filter(which I don't think I have to explain how?). Get the oil pan, and make sure it's right underneath the filter. If not, you're going to have a mess all over the place. So this is a simple yet important step. You don't want to spend even more time cleaning the driveway, than changing.
Go and drain the filter. Unscrew the drain plug from the oil filter. It's a big looking bolt, unscrew with your wrench or ratchet and let the oil drain in the pan. Once the oil is drained in the pan, screw the plug back on, to avoid a big mess(there will probably still be oil in the old filter).
Take the filter off. Take your oil filter wrench, going counterclockwise to remove the filter.
Put in the new oil. Take some new oil, dip your finger and spread over the rubber gasket end of the filter, that you'll be using to screw on. Fill the filter up about 2/3 of the way, not completely full.
Put the new oil filter on. Clockwise, tighten the filter with your hand, as tight as possible. Until you can't get it anymore tighter (no tools here).
Get up from underneath your vehicle. Unscrew the oil cap on the engine, take your funnel out. Fill it up with oil. Check the car manuel, to see how much oil your engine takes.