Ask HN: What can my non-tec co-founder do before our launch?

Hey!

We're building a social media platform. Its target group on long term? Anyone. Like Facebook, like Twitter. And the bad thing as usual with this kind of startup ideas: it only works with a lot of people.

I want you to throw in ideas: What can my non technical co-founder do to market the app upfront and after launch? He can only do things where it is not neccessary to develope. What would you do?

Consider all business-related tasks as done (strategy, business model(s), etc.).

Note: he has "fulltime". 3-4 month until launch.

Thanks in advance.

Best regards the ug dev