Different drawArrays modes in WebGL

I find there are several mode in drawArrays function. They are POINTS, LINES, LINE_LOOP, LINE_STRIP, TRIANGLES, TRIANGLE_STRIP, TRIANGLE_FAN.

As I know (and I hope my understanding is correct):
LINES can draw a line between two coordinates.
TRIANGLES can draw a triangles with three coordinates.
TRIANGLES can draw a rectangle with four coordinates.

However, I don’t know the mode of POINTS, LINE_LOOP, LINE_STRIP and TRIANGLE_FAN.
How can I use these mode to draw a model?

Assume, I have a list of coordinates that can be used to draw a cube (4 coordinates * 6 face = 24 coordinates), which method is the best to line to link up the edge of the cube? And which method is the best to draw six face?

Also, is it possible for me to draw the lines without the index buffer?