One other thing, we all think NBs sleep loads! Mine didn't. He spent a lot of time screaming in pain until we got feeds under control. He slept when he was exhausted and could sleep through the pain. Nights were much better than days for some reason.
I also gave him too much A time too early because I was trying for 3hr EASY 1.5hr A, 1.5hr S. Sounds silly now, but that was my FTM mistake
Starting as you mean to go on in regards to the big things is important - the order of the routine makes it way easier to ST, sleeping LO in his cot for nights (or knowing that you have to transition him slowly to his cot if you choose to co-sleep). This is not a strict by-the-clock routine, its about making it easier to tune into your baby's needs. If you've just fed him, his cry is more likely a tired/I want cuddles cry than a hungry cry, yk?
As a new mum with a c-section that reached from one hip to the other, I did 1.5hr straight of shush/pat over the side of a cot trying to get a screaming 4 week old baby to sleep "because he needs sleep!" Eventually I had to walk away from him for a minute because I caught myself screaming at him "why won't you just f^%*ing sleep?!" I had undiagnosed PPD after a somewhat traumatic birth and I was taking the book too literally. I had an idea from 'starting EASY at 4 months or older' stuck in my head - do shush/pat for the whole length of the nap, then get LO up and carry on with the day. Eventually LO will learn to sleep in the cot.
I ST'd L successfully for day naps in a cot at 4-5months. Prior to that, he slept in the cot every night but for naps, it was the pram, swaddled on the loungeroom floor, in a baby basket in the laundry, wherever I was at the time. I followed EAS order and used the average A time as a guide on when to give him the opportunity to sleep. This meant that when I went to ST for the cot, he had the right timings for A and S, his body was used to sleeping, etc. so the only thing he was learning was sleeping in the cot. ST is so much harder if you're also trying to figure out the timings that suit, esp. after 4 months.
STing before 6 months makes things easier for training and to prevent further difficulty with sleep. At 6 months, LO's have a developmental leap that allows them their first realisation that you are a separate being from them and that you *can* go away. Its also the time that most LO's need to be able to recognise their surroundings if they rouse at 45min in their nap so that they can get back to sleep. For that, they have to go into bed awake enough that they can see where they are so they can resettle themselves. Developmental leaps along the way, as well as teething, illness and life in general will at times have your routine flexing (or seemingly breaking), so keep in mind this is a routine, not a schedule.
I just am trying to set you up with expectations that are a bit closer to reality. As a pregnant woman, I thought I would do EASY from day 1 and I'd have a perfect routine and everything would be predictable. As a new mum, I resented L's grandmother for holding him to sleep when he was 6 days old, I was smiling on the outside but fuming on the inside that she was setting me up for failure. I now know that babies need a lot of cuddles and they're not awake long enough to get them all while they're awake when they're NBs. That need for affection is not a 'want', its a need - for emotional development and wellbeing.
Basically in the first 13 weeks (when he's tehcnically a NB), you're transitioning your baby from his entire experience having been in your belly to the much harsher outside world - the easier you can make that transition on him, the better. Just being out and experiencing light, sound unimpeded by your flesh is an assault on his senses.
We'll be here to support you through the weeks, months and years ahead.