So day starts at 5.30/6 anything before that unless he is crying leave him in his cot. I he starts to cry for you then go in, shh/pat or if there is no way he will sleep sit with him in the dark quietly until then, then start the day, lights on etc.
I would try this for the naps, feel free to move from this, it's a starting point right
WU 5.30
Nap 9.30-10 wake at 30 mins
Nap 12 for as long as he likes. If he wakes before 1.30 keep him in his room and try to get him back to sleep, or if he loses the plot, sit in the dark. Nap is 1.5 hrs long minimum.
BT if he short naps then 6pm BT if he sleeps past 1.30 then BT is after 5hrs A time.
The short nap in the morning itwill make him tired enough for a pm one.
For BT routine, if you want him in bed at 6.30 then he needs to be in the cot by 6.15...the first night will be tough, he will fight it. You can either go straight for the cot, or move him to the cot when he is very tired and sleepy.
NW - yes keep him in the cot if you can. Even if you have to cuddleto chill him out then PD that's ok to start with. No BF to sleep but if you want to do one Bf that is fine. Pick a timeand do not feed if NW before then.
Now...this WILL be hard okay...first 3 nights may be pretty rough, but you have to think positive and know that he is used to this and you are taking it all away from him s o he will be confused, tired, angry and weds to learn to sleep on his own.
Lastly. Do you have a lovey for him? This may help the transition.
With the BT routine, maybe just do feed then unlatch, sing twinkle twinkle or something then in the cot with a hand on him (pressure)