1) Welcome to the twcenter forum
2) You need to position the render cordons to set the piece you want to render. As you can see in the tutorials there are black vertical lines in the start and the end of the time line, you need to drag them to your keyframes in order to restrict the rendered footage.
3) I'm not completely sure but I think you can delete the first keyframe with the "Del"-key. If it doesn't work you can still make another keyframe where your scene starts and move the camera with that keyframe selected...
Hope it helped,
D|need