Getting a WhatsApp Business number onto the Cloud API used to mean digging through Meta's App Dashboard for a WABA ID and a Phone Number ID, then separately creating a System User in Business Settings to generate a permanent access token that wouldn't expire the moment someone logged out. It's not hard once you know where to look, but it's a lot of copying values between browser tabs.
The Setup Guide now has a "Continue with Facebook" button on step one. Clicking it opens Meta's own Embedded Signup popup, where you pick or create the WhatsApp Business Account and phone number you want to connect, the same way you'd expect from any "Sign in with" flow. When it finishes, your Phone Number ID, WABA ID, and a long-lived access token are filled in automatically — nothing to copy by hand, and no separate System User step.
Manual entry is still there as a fallback for anyone who prefers it or is troubleshooting a specific value, but for a first-time setup, one click is genuinely all it takes. Combined with picking Coexistence or Full Migration for how the number connects, most businesses are sending real messages within a few minutes of starting the Setup Guide.