Babies, as we know, do not come with instruction manuals. They arrive helpless and floppy, then grow at an astounding rate—their brains wiring a million neuronal connections per second! Caregivers, you help baby’s brain grow through back and forth exchanges from day one: sometimes called “serve and return” interactions.

Here’s a snapshot from each month during this astounding period of growth, whether you’re about to experience all this in “real time” or you’re thinking back on your child’s first year.

MONTH ONE: This is the white-knuckle zone. There is no preparing for life with a tiny, loud human who doesn’t know the difference between night and day. Some call the first three months of baby’s life “the fourth trimester” because your best bet is to pretend they’re still connected to your body because that’s what they seem to prefer. Also: rest when you can and say “yes” to all help offered. The bonus of this time period is that no one really expects anything of you and friends and neighbors may even leave food at your doorstep.

MONTH TWO: You are still in the twilight phase, but if it’s any consolation, neck strength improves and your baby isn’t quite so floppy anymore. If you need to get anything done, strap your baby right to you with a carrier or wrap. With the baby still basically attached to you and sleeping a lot of the time, you can still get away with the occasional brunch date.

MONTH THREE: Many say babies “wake up” at this time. You start to see genuine smiles light up their little face. Baby’s vision is improving and they can focus on more around them. It’s the perfect time to get them out into nature or start reading to them more—since they can now focus on the pictures.

MONTH FOUR: Baby is trying to coordinate their hand and eye movements—it’s almost like you can hear them thinking: “If I could, just…get, these hands to work!” They might soon get their body parts to sync up so they can grab something, likely to bring it to their mouth. Also, watch for your baby’s emerging temperament. Do they like a lot of activity, or are they more mellow? Are they easy or difficult to soothe? No temperament is good or bad, but it can help to know which way your baby leans.

MONTH FIVE: You might still be able to count on baby staying put if you leave them for a minute. But some babies are starting to roll around or even creep at this age, so be advised. It’s disconcerting the first time you walk away from them lying on a blanket and come back and they’ve rolled right off! 

MONTH SIX: Half a year of growth and your little one can probably sit up with some assistance now. Your baby continues to benefit from your attention and responsiveness—you can’t spoil a baby. Talk to them about anything. The more language you use in your interactions, even just talking about whatever you’re doing (sometimes called “sportscasting”), the better.

MONTH SEVEN: Your baby might have teeth by now, or it could be another few months—who knows? Babies are tricky like that. Heads-up you’re supposed to wipe down their gums after meals even before they get teeth.

MONTH EIGHT: At some point in the next couple of months your baby will try crawling. They might start off going backwards, sideways, or even scooting around on their belly or bottom. Time to babyproof if you haven’t already.

MONTH NINE: A classic milestone at this age is what’s commonly referred to as “stranger anxiety. ” This accomplishment means that your baby has gotten mature and aware enough to know that they belong to you and vice-versa. When meeting someone new they may let you know: “No, I do not want to be held by this relative or child care provider, thank-you-very-much.” Try to take it as a compliment.  

MONTH TEN: Your baby is probably on the move in one way or another by now. And while it might seem like all their energy is going into mobility, they’re also growing leaps and bounds in their language abilities. Your baby takes in everything you’re saying. Even though it will be some time before they start actually talking, baby understands a lot of your words and gets their own points across with nonverbal communication like grunts and gestures.  

MONTH ELEVEN: Curiosity is the hallmark of this time. You baby is an explorer—a tiny scientist. Watch as they experiment with cause and effect: dropping items from their highchair, splashing their pudgy fists in their food and dumping out bins of toys. All in good fun and learning.

MONTH TWELVE: Wait, how did that year pass so quickly?All that growth happened in the blink of an eye. You baby went from an uncoordinated, unfocused, and flailing baby to a mobile and babbling little person. They definitely have their own personality at this point and it will be difficult to imagine a time when they weren’t a part of your family.

Once baby is a year old, they will likely be walking, and you can technically call them a toddler. But let’s be real, they’ll always be your baby.

Sarah MacLaughlin is author of the award-winning book, What Not to Say: Tools for Talking with Young Children and has been featured in The Huffington Post. She’s writing new book Raising Humans With Heart: Not A How-To Manual. A human development nerd, she brings over 25 years of experience working with children and families to her coaching practice. Sarah is also mom to a tweenager who gives her plenty of opportunities to take her own advice.