I am having a trouble reading chords with four-noted beams.
Do they divide up in half as marked in the picture?
And also, the score is in non-SATB setting, I assume it is because "Harp" is written by the score.
What is the difference between SATB and non-SATB setting?
I'll give an even simpler answer:
These are eighth notes:
So are these:
They're all eighth notes because they have only one (horizontal) beam line. Even though they look different, they would sound the same. Each note is half the length of a quarter note.
Similarly, these are sixteenth notes:
... and so are these:
... because they all have two beams.
And also, the score is in non-SATB setting, I assume it is because "Harp" is written by the score. What is the difference between SATB and non-SATB setting?
Yes, this appears to be harp music. "SATB" stands for "Soprano, Alto, Tenor, Bass," common sections within a vocal choir. Music for a four-part choir might be written with four individual staves, or it might be compressed onto two staves (the "grand staff," like piano music) to save space, as is often done in hymnals. When written this way, we usually make it easy to see which part is which by making the stems point up for the top voice in each of the two clefs and down for the lower voice:
You can spot this kind of music, that has individual "voices," by these differently-pointing stems, but also by connecting the dots to see the lines: in my example, every voice moves up or down by only one step at a time, and this helps us hear its notes as a melody of its own.
But music that isn't written for choir doesn't always have four parts. Harp, like piano, uses the grand staff to easily notate its wide range. There's no reason for it to use four-part writing. Sometimes harps or pianos play only one note at a time and sometimes chords. The notes are arranged on the clefs based on their pitch or sometimes by which hand is supposed to play them. Sometimes instruments might also play music that contains multiple "lines," like choir music, and it's common in these cases to use those different-pointing stems to show the melodic relationships. Even if it does this for a while, though, there's no reason it has to stay that way throughout.
A chord change may come at any time (even mid-beat, though that isn't exactly common). The notes are grouped to the beams based on timing (first and second beat: one beam, third and fourth beat: one beam, if they're eighths), not on chord changes. Each frame you made contains notes from one beat.
From the notes, it looks to me that the first two frames are each a different chord, and the second two frames are one and the same chord. I'm sure you can figure out which chords they are.
It took me a while, but I think I understand your confusion.
The eighth notes are beamed into groups of four eighth notes per beamed group.
If you though beam group is meant to group notes by chord, then this grouping could be confusing, because there are two chord per beamed group in the first pick up measure. But the second measure, the first full measure of four beats, has two chords Eb: I IV6/4, which are arpeggiated, and grouped with four eighths beamed which matches up with the chord changes. There is a mix of beaming to chord change groupings.
The beam grouping is not about grouping chords, but about grouping rhythm. Grouping four eighths in 4/4 time helps to see the measure divided in half. Sixteenths will be grouped into fours to show how four sixteenths comprise one beat. Within those rhythmic groupings there may or may not be chord changes.
What is the difference between SATB and non-SATB setting?
There isn't really a difference in terms of grouping, but some vocal music uses beams only per sung syllable of text. That type of notation will seem to have lots of unbeamed eighth notes, but it's because each eighth is for a separate syllable of text.
