Summarize the following:
In order to learn a song by ear, you’ll need to start by getting thoroughly familiar with the way it sounds. Sit in a quiet room with no distractions and listen to the song on repeat for a while.  You may find it helpful to listen to the song with a pair of good, noise-canceling headphones. These will block out background noise and help you hear details you might otherwise miss. Spare your hearing by keeping your music device’s volume below 60% of its maximum volume, and don’t listen to the song for longer than 60 minutes at a time. out the rhythm of the song as you listen. Understanding the tempo and time signature of the song will help solidify the melody in your head. As you listen to the song, tap your foot, clap your hands, or snap your fingers along with the beat. Think about how the notes of the melody fit to the beat.  For example, “Twinkle Twinkle Little Star” has a 4/4 time signature, which means there are 4 beats to each measure of the song. In the first measure, there is 1 note per beat, with each syllable of the phrase “twinkle twinkle” landing on its own beat. In the second measure, the first 2 notes (“lit-tle”) land on the first 2 beats, and the 3rd note (“star”) is held for 2 beats. This pattern repeats throughout the whole song. Most songs follow some kind of identifiable structure, although the structure may vary depending on the genre of the song. Divide the melody up into recognizable parts, such as the intro, verse, chorus (or refrain), and bridge. For example, a typical pop song may have a structure such as “Verse-Refrain-Verse-Refrain-Bridge-Refrain.” Once you’ve listened to the song and analyzed it, try singing along while you listen. Even if you plan to play the song on an instrument, singing will help train your ear and lock the melody into your memory. Sing along until you’re confident enough to sing or hum the melody without listening to the song.  Work on singing the song in sections. Try singing the first verse, then sing the verse and the refrain, then add in the bridge and chorus, and so on. Keep working until you can sing the entire song without the recording. After singing the song on your own a few times, listen to the song again to be sure you’ve got it down. Unless you have perfect pitch, you will probably need to use an instrument to help you find the first note. After listening to the song, hum the first note and try to find it on your instrument. If you have to, listen to the opening of the song on a loop a few times until you manage to find the first note. Once you find the first note, write it down. Even if you can’t write musical notation, just write down the name of the note (e.g., “A♭”). Once you’ve identified the first note, your job gets a lot easier! Think about how the second note sounds relative to the first one. Is it higher, or lower? Does it sound close to the first note, or is there a big difference in pitch? Once you have an idea of where the notes are relative to each other, work your way up or down from the first note to find the second. Doing interval training (i.e., learning to recognize the intervals between notes by ear) will help this task come much more naturally. Try interval training exercises (like the one here: https://tonedear.com/ear-training/intervals) to help you develop relative pitch. Once you’ve figured out the second note, move on to the next. Write down each note as you figure it out, until you have the whole melody written down. You may also find it helpful to mark out the timing somehow. For example, you might write out the beats for each measure and write each note below the beat(s) it falls on. If you’re playing the song on an instrument, such as a guitar or a piano, consider what fingering will work best with the melody. This will take some experimentation, but if you’ve had a lot of practice playing scales and arpeggios, you may already have a sense of what works. For example, if you’re playing the melody on a piano, consider whether it might be better to cross your ring finger over your thumb to reach a lower note rather than move your whole hand down. Once you have your notes figured out and your fingering locked in, it’s time to practice, practice, practice. Play the song over and over until you can do it confidently without looking at your notes or your hands, if you're playing an instrument.  You may find it helpful to break the song up into smaller sections. Once you get comfortable with one section, move on to learning the next. Once you think you have it down, try playing along with the song to make sure you have the timing and melody right.

Summary:
Listen to the song over and over. Count Break the melody down into parts. Sing along with the song. Identify the first note of the melody. Find the next note on your instrument. Write out your notes in sequence. Work out the easiest way to play the melody on your instrument. Practice playing the melody until you have it memorized.