Sheet Guide (Important)
SB (Second Block) is the 3rd step of the Lin Method, in which
you solve the last two Corners of the D Layer + the Edge
in-between (similar to the Roux Method on a 3x3 Cube).
You might have heard of SBEC (Second Block Equator Control),
in which you solve the second block while fixing the equator
at the same time, but it's not the optimal way to do it,
so there is no point in learning it.
P.S.
In this Sheet the Second Block consists
of the white-green pieces, but if you don't like it, I also have
a video tutorial in the Other Sources section.