Hi, I am confused around guidelines for newborns when sleeping. Should arms be tucked in or out? My understanding was arms tucked in when newborn and after 3 months or when they start to wriggle that’s when should be arms free? I’m yet to decide on swaddle or sleeping bag. I see sleeping bags for newborns with armholes but yet I thought they should be arms tucked in?

Swaddling/wrapping (arms in) is a useful technique to help settle babies in the early weeks.
Once baby is attempting to roll, swaddling (arms in) need to cease a baby needs arms free to roll well. Most baies are rolling by 4-5mths.
Red Nose recommends using a light weight cotton or muslin material to use as a wrap/swaddle.
https://rednose.org.au/article/safe-wrapping-or-swaddling-when-to-stop-and-how-to-select-a-safe-sleep-bag

A safe sleeping bag (arms out) can also be used from birth but needs to be the correct size for the baby with fitted neck, arm holes , or sleeves, & NO hood.
https://rednose.org.au/article/what-is-a-safe-sleeping-bag
Most babies respond well to being swaddled in the early weeks, but some don’t. It is entirely your choice, or what works best for you & baby, whether you use a swaddle & then transfer to sleeping bag when baby tries to roll, or use a sleeping bag or neither.
https://rednose.org.au/article/how-to-dress-baby-for-sleep