Congrats! How old is he? what's his name? I'd love to hear more about him, this is my favorite breed after all
Of course you need to know typical puppy stuff, lots of chew toys, lots of positive experiences with lots of people and dogs. Make sure you socialize the heck out of him, bring him everywhere dogs are allowed! I also recommend clicker training for all dogs and pups, it lets you focus on all the good things your dog does so you don't focus on punishment. Instead of always remembering to punish the dog for doing something wrong you can avidly search for everything good your dog does so you can reward him.
As far as APBT specifics the bad stuff is Dog aggression and ignorant people (of course that's not the dog's fault). In this breed having a dog who hates other dogs is not always the fault of the owner or lack of socialization (though that can be a cause) it can be simply his temperament,l something you cannot fix but can CONTROL and manage which you must. As a pup you should treat him like any other dog, remember to socialize with other dos every day you can, try to seek owners out (when on a walk don't wait for the other owner to ask interested, ask if your dog can meet theirs and if he is friendly) and keep the experiences pleasant. If as adulthood approaches your dog starts showing Dog aggression you'll need to begin training him to focus on you on command or by sight of another dog.
As far as ignorant people you will encounter people who yell at you for saying their child can pet him or will tell you he should be put down. They may tell you he is going to turn on you and will give you looks. You may see a child ask their mom if they can pet the doggy and hear mom say "no those dogs are mean". If you can educate them, if you can't let it roll off of you, you cannot let stupid people ruin your day.
Now for all the rest (depending on you it could be good or bad, for me it's all good!). These dogs LOVE people and are great with kids. they are very active and need lots of activities, not a couch dog that's for sure. So I'd pick up a hobby like swimming, hiking or bike riding so you can bring your pup along. Also lots of playing and trips to the park (human park, not dog park, you cannot guarantee those dogs will be friendly or healthy so you don't want a puppy there) . Those trips will be good for socialization. They are real goof balls and have a great smile. They are determined so will not back down if there is a chance they can get away with something. This does NOT mean you have to be harsher with them or punish them more or "dominate" them by physically pushing them around, it just means you have to be persistent with what you want or will not allow. If the dog is begging don't give in, if he will not listen to a command don't let it go unnoticed, if you have to stop and do a mini training session to be sure he understands what you are asking.
We have many APBT owners here, they are all great dogs and I cannot wait until I can rescue one. If you need any training help do ask!!