While the above poster is well-meaning, I would caution against his advice of "wandering around" if he meant to do that during the ceremony.
Not only is it considered distracting and unprofessional to do much "wandering" during the ceremony, but the term sort of implies handholding the camera and "Hank's Rule of Handheld Shots" says that they are best done only when you have a moving subject, moving camera or both - and even then, only sparingly.
He makes a good point about having two videographers, though. Weddings are perfect events for husband and wife team coverage. The wife shoots the bride's preps in the dressing room while the man covers the groom tying his shoes, getting his boutineer put on, etc.
The classic positions for wedding ceremony coverage is to have three cams. One cam in the back, wide (not medium) generally unmanned. The other two cams are positioned behind the wedding party, at the corners. Camera #1 is behind groomsmen and has the best shot of the bride. Alternates between full, medium and cu, with emphasis on full and medium so that it nearly always has a usable shot. Cam #2 behind bridesmaids with best view of groom.
Cam #2 may "wander" by panning on tripod to shots of parents and other guests, bridesmaids, groomsmen, cu shots of groom and bride and cu of ring placement. A bit of moving around may be required to cover groom's reaction to bride's entrance, Unity Candle ceremony, singers, etc. Never cross over, in front of or behind "center stage", but stay on your side.
We're in production of "Wedding Video Done Right", but because this is the wedding season (May through October), we don't anticipate release until early next Spring.
You didn't ask about mics, and that isn't surprising seeing how even many "pros" don't bother to properly mic a wedding ceremony. But, if you want a truly professional wedding video, you must mic all sound sources (except the crying baby in row 3).
Mic the minister, groom and father of the bride. Mic all singers, speakers and music sources. Except for "last resort" backup, shotgun mics have little place in wedding ceremonies. Use lav mics on all speakers. Handheld mics or shotguns mounted on stands for quartets, piano, singers, etc. are OK.
Built-in, camera mics are totally useless during ceremonies.
Good luck to ya!