Winter Break (sample)
Here is another boogie song, but it is straight 8ths instead of a shuffle (8ths Boogie). The song is in the key of A, but the Choruses are in E. I wrote down and circled the new keys in front of each section that modulated just to keep myself from getting confused.
For the Intro, there are 2 bars of rhythm guitar pickups before the lead guitar comes in with the Verse melody. At the end of the Verse, "Mod to 5" means modulate to the 5 chord (E) of the original key (A).
Look at bar 8 of the Chorus. There are 3 eighth notes showing the rhythm played for the 2nd half of the split bar and no notation for the 1st half of the bar. If there is no other rhythmic notation in a split bar, it is assumed that the un-notated chord of the bar gets regular rhythm and lasts until you get to the notation. So, for a syncopated split bar like bar 8, you play the 1 chord until the 1st half of beat 3, and play the flat 7 chord on the "and" of beat 3 as notated. All this is to say that in a measure like this one, the duration of the 1st chord of the bar is implied and does not need to be written out to understand the measure.
The only thing different with the rest of the song is the last measure. Here, the 4 chord gets 4 eighth notes, so we know that the 5 chord in that bar lasts for 2 beats.