Re: What does this mean?
Well if you turn on the N64 and you happen to have the control stick pushed down/left/right etc. then the game takes that as the default position of the control stick. So then if you let go of the control stick and don't touch it, the cursor on the screen will move by itself. So if the little Diglett on that screen moves by itself, that means your control stick isn't set to the default position correctly and pressing those buttons will reset it.
As for beating the game, was there any particular part you wanted help with? Like particular gym leaders or tournament types?