1) how to make a window full screen
2) how to do collisions
Take a look here:
http://forum.thegamecreators.com/?m=forum_view&t=95770&b=7 there are lots of examples but I would recommend sparky's...
3) how to do gravity and physics
Sparky's comes with some good examples of how to achieve something pretty good.
4) how to move the character
Again sparky's examples will show you this.
5) how to have things appear out of the character (ex. ninja stars swords)
I suggest getting off the starting block before thinking about the finish line. Take it as far as that for now then see what comes next... it'll take a while to get that far anyway!
6) Do I need 2 or more dba files in 1 dbpro file
No, you can produce your whole game in one dba if you want. I personally find it easier to use several (it helps keep stuff organised for me).