Newbie camcorder user questions

Guys:

I've gotten this new digital camcorder and I have some questions which have aroused.

1) The manual keeps talking about "Gain". What is it? It says you have to be very carfeul when you use light to avoid having ghosts (?)

2) Which features are a "must" to master and which others are best to keep in automatic? For instance, you must learn in detail about image stabilization but not care much about white control

2) Even though I bought the camera on an NTSC country I plan to use it on a PAL one. I have not read anywhere on the manual that the videos recorded are by default on NTSC. Although I have installed a video editing software which has demanded which system I preferred. My doubt is if the original footage is in a predetermined format or the format you give it when you transfer the data from the camcorder to the PC???

Thanks