Use the `label` attribute to add a label on top.

```html
<sd-radio-group name="radio-group" value="1" label="Group label">
  <sd-radio value="1">Radio 1</sd-radio>
  <sd-radio value="2">Radio 2</sd-radio>
  <sd-radio value="3">Radio 3</sd-radio>
</sd-radio-group>
```