The flute keys aren’t like piano keys. There are fewer buttons than there are notes, so different combinations of keys (called fingering) are used to make different notes. The C scale goes from C (with only the left pinky) down to C (all fingers except right thumb, which just holds the flute up), with each lower note adding a finger on a key.
If that was more involved than you had in mind, sorry :).
tl;dr: Flutes only play one note at a time.