Printing uses Star PassPRNT — a free app that bridges the till to the Star TSP100III.

One-time setup:
1. Install PassPRNT from the App Store on this iPad
2. Open PassPRNT → tap Configuration
3. Set Printer to TSP100IIILAN
4. Set Port to TCP:192.168.1.2
5. Tap Save — done

When Print Receipt is toggled on, tapping Done — Paid will open PassPRNT, print, then return here automatically.