Click the button to Back up now. In macOS Catalina, you can access your iPhone through the Finder. When the backup is done, connect your new iPhone SE, then tell your Mac you want to restore from
4.7-inch (diagonal) widescreen LCD Multi‑Touch display with IPS technology. 1334x750-pixel resolution at 326 ppi. 1400:1 contrast ratio (typical) True Tone display. Wide colour display (P3) Haptic Touch. 625 nits max brightness (typical) Fingerprint-resistant oleophobic coating. Display Zoom.
On your new iPhone, go to Settings > Mobile Data > Add Data Plan. Choose a mobile data plan to transfer from another iPhone. If you don't see a list of numbers, tap Transfer From Another iPhone. This requires both devices to have iOS 16 or later. Check for instructions on your previous iPhone to confirm the transfer.