To help myself find the many answers to that question, I've been making some observations over the course of starting about a half-dozen different worlds with lots of different settings configurations. In other words: How does this thing work? Every game has its own unique answers to that question, and it usually requires spending time with it to figure them out. While questions like 'where do I get wooden planks?' and other specific questions about where to find resources will come up after you've been playing for a while, the struggle in the really early goings is just in understanding Lego Fortnite's fundamental logic. Yes, there's a tutorial, but it's also an open-world sandbox game in which it's very easy to get distracted by some new thing and lose track of what you were supposed to be doing.
As is the case with all games like this, there's a meaningful learning curve involved in getting started. After a year of rumor and innuendo, Lego Fortnite has arrived and injected a major dose of survival-crafting into Fortnite.