<human>: Can you provide a brief overview of the text?

You guys have been super helpful in the past, so although I've been reading up plenty on introducing a new puppy to my cat, I thought I'd see if y'all have any tips.

The situation: my cat is a 4 year old, 15 lb Maine coon mix that I adopted when he was a kitten. He's pretty chill - he's (mostly) leash-trained, can "come" and "sit" on command, loves car rides, very people-oriented, never sprays. (I didn't know anything about cats when I got him so I just pretend he's a dog half the time.) He's lived with dogs before for 1-3 months at a time; he's not a fan of big dogs (and HATES other cats), but he is fine with dogs his size or smaller. He does tend to be pretty "alpha" in these relationships once he gets to know the dog.

The puppy is a ~3 month old pom/chihuahua mix who currently weighs 7.5 lbs and is unlikely to get bigger than the cat. He's not house or leash trained yet, so we'll obviously need to start there. Both animals are fixed. Otherwise, I don't know the puppy yet - he's arriving this weekend from a rural shelter down south.

We live in an apartment in Upper Manhattan - it's quiet and large, for Manhattan, but will probably still be small and noisy for the country pup. That also means that we'll have to leash-train immediately since we have no yard access. I've got a wire crate for puppy and have moved my cat's food and litterbox to high surfaces where they're safe from the dog.

So that's the scenario. Tips or personal experience with introduction and getting these guys to live peacefully together? Most of the things I read involve not scarring the cat for life, which I certainly don't want to do, but with this size discrepancy and the fact that the cat plays pretty rough, I'm actually just as worried about the cat hurting the dog.
<bot>: big, confident adult city cat meets small, country-bumpkin puppy - how do I make the introduction/do you have a similar story?