Well, there's a first time for everything, lizard! As I have a chicken in the fridge waiting to be roasted this very evening, this is what I'd do (and, indeed, will do):
Making a note of the weight of the bird first, which should be on the label, take it out of the wrapping (erm...OK, obvious enough) and pat it dry. I like to remove any stray lumps of fat that might be clinging to the skin (rummage about inside a bit) because they just make extra oil that you'll probably want to get rid of.
Put it in a roasting-tray and stuff any of the following up its cavity:
a halved lemon/head of garlic cut in half/generous bunch of herbs such as thyme or rosemary (all of the above, if you like!)
Season the chicken's skin generously with salt & pepper.
Place in a pre-heated oven (Gas 5, 190 deg or so) and roast for about an hour and a half if it's an average-sized chicken of around 1.5kg. You can baste it a couple of times if you like (take it out and spoon some of the juices over it while cooking), but there's really no need. It should be done in this time. To make sure, get a sharp knife and stick it into the chicken leg where it meets the body. The juices (there should be some!) ought to be clear. If they're pink, ie still a bit bloody (sorry), stick it back in the oven for a while longer.
Remember not to carve it for 15 mins or so after it's done - you can cover it with foil to keep it hot. That way it'll be good and juicy. You don't need an electric carving knife, which imho just reduce any meat to stringy shreds. Just use a good sharp knife.
Actually I'm feeling hungry now!
There's no great mystery about this and if you Google Jamie Oliver, Nigel Slater, or any of that lot, they all have recipes for basic roast chicken. There are variations and you can roast extra veg in the pan with it if you like, but basic is fine.
Remember that if you buy a supermarket chicken it will probably say on the wrapper how long to cook it for, and at what temperature.
Good luck!