I know what you mean; why are there red "tweety birds" on the chart
I usually ignore the things I don't use (and don't know what they mean).
I mostly use mine for "contour lines", shading between shallow and deep water, and most often "predicted current".
The current is the ARROW showing incoming or outgoing.
The tide is a rectangle bar.
By touching the screen, you should get a crosshairs that you can move on top of an icon to find information about what you just selected.
But those birds
Who knows?
5th