The coda here is the final bar. Coda means "the tail" In this case of LET IT BE it is only one bar.
Does the Dal Segno symbol mean "repeat the previous passage"?
D.S. (Dal Segno) means "from the sign" and this is the sign right above the double barlines (something like an $:
Up to where?
this segno refers to an earlier same segno, probably at the beginning of the 3rd verse of LET IT BE or at the beginning of the refrain.
That means you have to go back to the other sign (segno) and repeat this section until you come to "to coda" (sometimes it's written "last time to Coda").
When do I play the coda?
When you play the refrain for the last time you have to ignore the 3 last bars (before the tail) and skip from "to Coda" directly to the coda and play the final bar.
When do I play the coda? Where it says "To Coda", is the circle with
the cross through it hovering above the exact place that you jump to
I'm probably overcomplicating a fairly straightforward concept here ...
D.S. al coda, or dal segno al coda, literally means “from the sign to the coda mark.” D.S. al coda is an indication to start back at the segno, play until you encounter a coda, then skip to the next coda to continue.
I've found this sheet music by scribd (the added notes/remarks are not mine!)
But you can see here the segno at the double bar line in the beginning of the verse: