1=D means that the tune is d, and it is no problem to play with f, and different tunes only have different pitches, and others have no influence-except of course ensemble. If you are a beginner, it is recommended to learn F key first, and at the same time insist on playing long notes for at least 15min every day. Long notes, fingering and enunciation should be compulsory courses every day. I suggest listening, watching and practicing more. Learning flute requires a little knowledge of music theory. There are some music theories that Uncle Ge can refer to on the Internet.