Seriously, take it to a professional. Changing oil is one of the most basic maintenance jobs, but if you don't even know what the plug looks like, I can think of at least three things you can accidentally do that could land the car in a junkyard.
Do you know how much oil to put in? And when to put it in? And when to check the level? Saw what happened to a fellow after he added oil when he stopped for fuel for his Volkswagen. Less than a mile later, in front of where I was working, I stood around with a dozen other people and watched as his engine self-destructed right in front of us. Ignition switch was off, key was out, engine was running wide open and wouldn't stop until it died, which took about five minutes. Air bubbles coming out of every gasket. He destroyed a two-year-old car because he didn't know how to check his oil.
The professionals will check your other fluids, belts, hoses, battery cables, tire wear, and bulbs. Do you know what happens to rubber seals in the brake hydraulic system if you have oil residue on your fingers when you check brake fluid level?
Very often you can find oil change specials that don't cost much more than you're about to pay just for the oil and filter.