How to become Founder’s Intern - I will not promote

Long story short: cold outreached the founder of a consumer software startup that recently raised a seed round. We went to the same college, he liked my approach, and we ended up scheduling a call. Call went well. Started with intros, then talked through the company, where it started, where he wants to take it, growth, product, scaling etc. Eventually convo shifted to me: what do I actually want from him, am I more technical/product focused, what am I trying to learn? Explained I’m product focused, recently built and wound down my own consumer startup, and want to get much better at growth because I think that’s increasingly where the edge is. Building is getting easier with AI, distribution is still hard. His company already has a strong initial wedge, so I basically said I’d love to work closely with him and take problems off his plate that he doesn’t have bandwidth for. He was pretty direct that I’m still early and don’t really have a highly deployable skill set yet. I basically said that’s exactly what I’m trying to develop. Then it became more personal: what’s your family like, what are your spikes, what’s the most impressive thing you’ve done etc. Thought that part went pretty well because by the end he suggested we meet in person a couple weeks later. That meeting is coming up now, and I’m trying to figure out how to approach it. My read is that he’s at least open to potentially bringing me onboard in some capacity, and the in-person meeting is partly just seeing whether we actually get along / whether there’s a fit. So how much should I actually prepare for something like this? Do I basically show up, have a good conversation and see where it goes? Or should I treat it more like an informal interview and be ready for another round of questions about what I’m good at, what I’d work on, why I want to join etc? I’ve also spent the last few weeks systematically analyzing their consumer base as a side project and have some genuinely interesting insights. I was planning to bring those into the conversation naturally where relevant, rather than showing up with some giant unsolicited deck. Curious how people who’ve been on either side of this would approach it. What is the founder actually trying to figure out at this stage, and what should I be trying to demonstrate?