bathroom waste drain

hi all,

I want to put a waste drain in the floor of my bathroom, where no exists. I'm not sure how I should prepare the floor. How big do I cut the hole? I guess what I'm worried about is making the hole too big and not being able to fix the drain in place. Just for for completeness, how is the waste drain fixed in place?

Thanks,
Stoo

Its usuaslly a brass fitting with a nut and thread underneath.

By using a leak control flange which will be larger than the hole,and screwed to the floor.

Tools