Unless you are the 1 in 10,000 who has perfect pitch, you’ll have to feel your way to the right note.
Along the way, the difference between what you are singing and the note you are tuning to feels bumpy. That’s the harmonic effect of sound waves being out of sync. The frequencies are discordant.
At first, it takes a little time and experimentation. If you don’t try you’ll never know. But once you’re there, the sound feels settled and you’re free to explore the tune because you’ve got the key.
What’s even better is to sing with others. Creating harmonies and countermelodies that fill the air with beautiful music.
What a glorious idea…