I've photographed pretty much everything in every situation possible, except weddings... People are too demanding and I don't think I ever saw someone really happy about their wedding pics, either they were not good enough or if they were, the photographer was too expensive... Those photos will be memories that they'll want to show off and cherish until death do them part... I just don't like that kind of pressure
Back to your challenge. First off the technicality: You'll have to check with the priest what is their policy regarding wedding photographers is, I've seen some churches were the priest acted kind of like the director, no photos unless he said so. (inquire about flashes while you're at it). You should "Survey" the church ahead of time to find good spots to shoot from and check the lighting in different weather conditions (take some test photos too). Also, the Kx is not known to be the quietest camera, the shutter and the mirror clap can (and will) get very annoying during the ceremony.
For the shooting itself, a naturally well lit church may still be very dark, especially if it's overcast outside. This will be very hard to predict and even harder to work with. You may have to use artificial light and the popup flash although practical, IMO it will not give you anything looking professional. Unless you're some sort of wizard with it. So consider using external flashes (if allowed). The same will be even more true at the venue where the reception will be, you will need artificial lighting.
For your lenses, I'll let the wedding photographers of the forum answer this one. One thing I can say for sure, get the best lens you can afford...
For the technique, whenever I was presented with a photoshoot I never did before, I would go online and look at thousands of pictures of similar shoots. I'd check the focal length, camera settings, lens used etc to try to have a rough idea of what others would do. Not to copy them, everyone has a different style. But it will give you an idea.
Also, talk with the bride-to-be. She has more than likely went though a million wedding photographs while planning her wedding... Ask here to show you some photos that she likes and take notes, try to figure out how the photographer got his shot, what distance he was standing, etc. Again, you don't have to copy the shots, it's just to give you a good idea of what she is expecting and what she likes.
If you can, try to do at least a preliminary casual photoshoot with them. And if you can, try to snap some candids of them too. This way, you'll be able to figure out if they have a better "side" and at what angle they look good (not everyone look their best and every angle) and you'll get some practice of taking pictures of them together.