As Liz says it is whenever baby wants to and for as long as baby wants to which will be different for each baby. 8-12 times in 24hrs. There should be no scheduling unless as Liz says they are sleeping past 3hrs (maybe 4, especially at night for full-term babies) and you need to wake them. Sleeping lots can be a sign of not feeding well so doesn't necessarily mean they are getting enough in the early days. The BFing lady at my hospital recommended keeping baby actively feeding for at least 30 mins i.e. Wake them to feed more if they fall asleep earlier but DD was done in 25mins mostly so I figured that was fine.
Sometimes they might take a full feed, sometimes just a quick drink.
My DD is 5wo and has fed mostly 3hrly since birth, often with me waking her. She took 25 mins to feed in the early weeks and now takes about 15-20.
DS1 took 45 mins to feed at the beginning and rarely went more than 2hrs in the day for weeks, apart from when he was very sleepy in the first few days.
DS2 was different again.
It shouldn't be a prescribed thing but rather mum should be led by the baby.
There is more official info on the LLL website.
http://www.llli.org/faq/frequency.html
