Ferber method

Even those who advocate for sleep training would say 3 months is too young.

Heysleepybaby on Instagram has lots of great info on baby and toddler sleep that isn’t sleep training.

Personally I would try other things first before resorting to sleep training, especially at 3 months. Trying for a crib nap for the first nap of the day can help practice since sleep pressure is the highest then. And there are lots of different tricks for transferring, sleep associations, etc.

I would say wait until at least 16 weeks/4 months for any formal sleep training methods, however that doesn't mean you can't alowly integrate things in the meantime. Ie try putting baby in the next to me and patting, holding the chest shushing for a minute at the start to see if they will settle.

Also they could find a next to me and cot too big so get a moses basket if you havent already. My first only slept in my arms til 8 weeks because she found everything too big, a moses basket was a game changer. My second loved the moses basket and slept there easily and transitioned well to the next to me after he outgrew it.

Make sure nights are dark and quiet and days are loud and light and set a good nighttime routine before bed.

I would also use a muslin or a tshirt which has their milk smell/your smell as a sheet so they have your smell nearby. This is what helped us be able to now put my 4.5mo down. X