Newborn Kittens Going to the Bathroom

Ok so most of you regulars know my Jada is due with kittens soon. My question now is what to expect with the kittens in regards to going to the bathroom. Should I expect them to go all over "their" room? I had my spare room picked out as the room I would giver her, but I am having second thoughts because I am not sure how much of a "mess" to expect. 

I have never gone through this, and I know cat urine can be impossible to remove from carpet or furniture. How bad should I expect it to be? Do they go in their bedding to begin? 

I know this my sound stupid, but I have no idea. THANKS!!! 

Jada will stimulate them to go at first and she should take care of the mess.  Litter training and what types of pans and litter to buy I'll leave to the others to explain.