Teaching my son

This is a dumb question but I'm a FTM and haven't really been around babies enough to know. Am I supposed to teach him every milestone? Or will he figure it out instinctively. I know that's stupid to ask but I was showing him to hold his bottle. He will put his hands on it if I dont touch him but if I try to put his hands to it, he pulls away and doesn't want to. Same with sitting up. If he's laying down, he's starting to pull his head forward when he doesn't wanna lay down or sit back anymore. I didnt teach him that. He learned himself. I know obviously some things like talking and walking I have to help him learn. But what are some other things I kind of need to work with him on? I dont want him to be too behind his adjusted age.