I have been meaning to post this for a while now as these routines were a bible for me and had my kids sleeping through the night by 3 months old and ever since! Thanks to the book 'A Contented House with Twins' - Please note is says "twins" and 'breast-feeding' but the routines work with 1, 2 or any number of babies, and with bottle feeding as well.
The routines start at 2 weeks as it is pretty hard to have much of a schedule prior to this point and some times weight and other factors affect when to implement a routine so consult your doctor first. I adjusted the times a bit to fit my household but kept the timing.
As with all 'advice' take it with a grain of salt and only use what works for you and your little one(s) as every baby is different and being a new mom is challenging. I sometimes adjusted the schedule by 15 mins to an hour if the twins were sleeping in. This is just a guideline, hope it helps!