Run car nice and hot
Ramp up car
Open Oil filler cap (and cover with cloth to prvent crap getting in)
Place big container underneath
Undo bolt (not usually tight)
Wait for oil to finish leaving vehicle (about 5 litres)
(good opportunity to replace oil filter if it needs doing as well, another case of unscrew/screw)
Change washer and clean up bolt
Screw back in, clean up mess, refill oil, lower car, check for leaks.
You've just completed a complete oil change.
Answer, if you hav ramps and the right sized spanner... easy.
If you have jack stands, a little harder... (only because you have to jack up the car)