The steps
- Connect to Wi-Fi and plug the device in (or keep at least 50% battery).
- Open the update screen:
Settings → Software update → Download and install - Download the update, then install it. The device restarts once; your apps and data stay in place.
Samsung also lets you schedule the install at night ("Schedule software updates") so it never interrupts you.
No update available?
Two possibilities: your device is already up to date — or it has reached its end of support and will never receive updates again. Check your exact model: