I was overestimating what DS could do. Newborns and babies of a month or so really aren't capable of staying awake for long spells. And it's easier to get an alert baby to sleep than an overly tired one. Err on the side of caution. One phrase I heard banded about was 'sleep begets sleep' and actually with experience I found that the more I let my newbie sleep, the more he would sleep and settle easier.i tried to keep him awake so he'd be tired but it was actually counterproductive.
Found attached chart as I searched for Elizabeth Pantley (sleep guidance) I read her book with DS first time around and it made a lot of sense but don't be bogged down with facts and figures, just see what works. I'd say an hour after getting up, it's time to nap! Get the pram, the bouncy chair, a boob, a dummy, a sling, the car, the hairdryer/hoofer and get them back to sleep!!
But don't obsess over it. I did first time, it was my every waking thought, counting hours, calculating, hypothesising, worrying. My new baby boy sleeps when he sleeps and is very content, he sleeps loooooads during the day as often we are out doing toddler things so he snoozes in sling/pram/car.
Sorry, that was a very long, possibly unhelpful, ramble! Sitting here with a baby that won't sleep anywhere off my skin 