<Stack direction="row" spacing={2}>
  <Button variant="outlined" onClick={() => setSelectedSectionType('month')}>
    Month
  </Button>
  <Button variant="outlined" onClick={() => setSelectedSectionType('day')}>
    Day
  </Button>
  <Button variant="outlined" onClick={() => setSelectedSectionType('year')}>
    Year
  </Button>
</Stack>
<DateField
  inputRef={inputRef}
  selectedSections={selectedSections}
  onSelectedSectionsChange={setSelectedSections}
/>