Replying to Videoing a Wedding

Long story short the person who was employed to video my friend's sister's wedding has pulled out at the last minute and I have been roped in to do the job instead.

I've never videoed anything before that wasn't on a gopro so I have no idea what I'm doing. I have a classic point and shoot video camera.

Has anyone got any tips for me? What do I need to capture? What type of things should I be looking to capture? Is there anything I should focus on? Would it be better to record for an hour straight or do it in small videos?

Thanks for any help you can give me!