Level relations

are the movie layers relative or static to the main time line?

for example…
if i load a movie into layer 1 from my main time line (layer0)

and i load a movie from layer1 to layer 2 is THAT move on layer2
or does it take the layer the clip is loaded from as 0

so would that clip be layer2 or layer4?

did that make sense??? its all so confusing