Begin by singing the solfege syllables along with the sing-long song. Be sure to take a breath at the rest. (For an explanation of shape notes, read Shape Note Sight Singing Success.)
Pay attention to the distance between the pitches, as this trains your internal pitch template, which helps establish good melodic tuning. The tuning for the sound files was specially chosen to foster solid melodic intonation.
The song tracks use synthetic voices rather than actual voices. Research has shown that this will help with the ability to identify and produce absolute pitch information. For more information, read Why Use a Synth Voice Instead of Real Voices.
After going through the song with the solfege syllables, try singing the Kodaly rhythmic syllables. The rhythmic syllables sit above the staff, while the solfege syllables sit below it. I have slowed the tempo of the song slightly so that it makes it easier to sing the syllables.
Just for fun, I’ve included a video of You’re a Grand Old Flag below.