This is likely a wild guess on my part but i've faced a similar feeling lately. If this comes from the realm of Webdev, React, SSR and all the F'ing acronyms that we need to learn today and you want to feel like you've "caught on": My advice would be to avoid NextJS at all costs. It's too bleeding edge.
Opt for a sane option instead to get started, likely one of these: (Astro, SvelteKit or Remix).
Opt for a sane option instead to get started, likely one of these: (Astro, SvelteKit or Remix).