One-time setup. Connect a shared database so you and your partner see the same checkmarks in real time — or skip and keep progress on this device only.
Option A · Shared sync (recommended)
Go to console.firebase.google.com → Create project (name it anything, disable Analytics).
In the left menu: Build → Realtime Database → Create database → choose a region → Start in test mode.
Copy the database URL shown at the top (looks like https://something-default-rtdb.firebaseio.com) and paste it below.
After connecting, use "Copy share link" in Settings — your partner opens that link and is synced automatically. Note: test-mode rules expire after 30 days; in Firebase → Realtime Database → Rules, set read and write to true to keep it working (fine for a puppy checklist — the link itself is the secret).
Option B · This device only
Progress saves in this browser only. You can connect a shared database later from Settings.