I want to bring to the back (wrap behind) a layer in QGIS and I have no idea how. Anybody knows how?
the layers I want to bring to the front
if I select every layer, the big one pops over
Select the layer, drag it to the bottom
JGH described the most straightforward way to do this. I would add a method if you, for example, have data in groups you don't want to change the order.
@JGH and @LaughU seems to cover it,
Perhaps think of the layer order panel like a stack of papers or transparency sheets for an Overhead Projector. The first layer in the Layer Panel list (first sheet), appears on the map first, anything below it appears on the map after it, as if you add sheets on top of the first sheet on the projector. You don't need to have Control rendering order ticked.
Top Layer - Appears on Map First
Bottom Layer - Appears on Map Last
@LaughU answer explains how one can reorder layers in the Panel list but fix the order in which they appear.