Swaddling will be your lifesaver with your newborn for the first few months. It helps calm and relax them. Just remember where they were for 10 months! In a cozy warm snug womb. They don’t know they have hands, arms or legs so they scare themselves if they move their arm in front of their face. They also have the moro reflex where they feel like they’re falling and flail their arms above their head when placed on the back. This reflex goes away around 2 months, which is also when you should stop swaddling.
Here’s a quick cheat sheet on how to swaddle: down, up, down, up.
Video demo (with a few other tips on soothing, side and shush!):
Make sure when you swaddle you use a square blanket. The best swaddle blanket I’ve found, and I’ve tried at least 4 types, is the Swaddle Design Ultimate Receiving Blanket. It’s thick enough that it keeps them warm, it’s the perfect size, and the right texture to help keep the swaddle in place. They also have a light weight version if you live somewhere really warm.