When you collimate a telescope, where is the center dot?

[Alby]

I was watching a Youtube video on how to collimate a telescope using
one of those laser collimating tools. In the video, they showed a
black dot in which you needed to align the secondary mirror to get the
laser beam on the center dot. But nobody said where that dot came
from.

I have an 8" F/6 primary mirror I bought from B&H. When I go to
collimate it in my newly built newtonian telescope, do I need to make
my own black dot on my primary mirror? Or does this dot just appear as
part of the laser tool I'd be using?

http://www.youtube.com/watch?v=yd3mjOr8rc0