From your question I'm assuming that you have never done an oil change before. If thats incorrect, very sorry.
I personally wouldn't run the engine up to operating temperature, a 5 minute run is sufficient. You want the oil nice and runny but not at about 80oC which will scald you very badly and much worse than water as it doesn't drip off so readily. When you have a bit more experience you can do it hot as you like but best be careful first few times.
Bear in mind that the sump plug is just about perpendicular to the floor - when you remove it the oil will arc out and hit the floor about 10 inches behind the plug, it will quickly move back towards the drain hole as pressure lessens until its just a dribble. Give it a few minutes to dribble then stick the plug back in with a new washer if you've got one. Re-use the old one if you dont. Leaving it for hours will only get you another shot-glass full, not worth the wait.
Remember that whatever container you use to catch the oil, you're gonna have to move it/angle it to catch the stream as it changes its arc. It also needs to be able to take at least 7 litres.
Removing the oil filter is easy in theory, lie on your back, reach up with both hands if you can fit, twist anti-clockwise on off it comes. Sometimes they're tight, try with a rag or old towel for extra grip. You may have to resort to an oil filter strap or wrench - it may be best to try and change the oil filter first - if you cant get it off you can still use the car to go out and buy a strap :)
As the lads above have said, oil usually goes everywhere when you take the filter off, I put a big old cloth I have over the axle under the filter. I like the plastic bag idea tho, I may nick it !
The most important thing to remember is to ensure the rubber seal comes OFF with the old filter. If it stays attached to the housing it will leak all over the place when you put the new one on. Wipe the housing with a rag, put a smear of fresh oil on the seal of the new filter and tighten it hand tight - do not use any tools to tighten it up.
New oil in (Don't forget :)), check on the dipstick when its just below the max. Run the engine for a minute, this fills the new filter, and top up again to the max line.
Thats about it, good luck !
Stu.
