HEADS UP: let the bike sit off for at least 20 minutes before you open the cover over the controller... those terminals are extra risky while some lingering charge might remain. See MVetter's comment on this later in the thread.
One of the very important Some Assembly Required actions is to grab a marker and add the ".5" to the SC version emblem
The SC box can go under the seat, at least on my '15 SR, where there's some empty space behind the controller. The controller itself is hidden under a thin black sleeve cover, held in place by a single screw in that rear open area. Remove that screw first, and then you can nudge the cover out a bit at a time... it's tucked under the frame bars just tight enough to keep it in place, hence only needing the single screw in the back as extra holding.
To get the cable that runs to the tail lights out of the way, there's one sharp-tooth clip holding the cable on the black U-bracket, running along bike stage-left
Once the controller cover is off, you can see the big bad monster wires attached to it. The three plates showing M1 / M2 / M3 will distract you from seeing the info you need -- the B- and B+ that are visible on the other two, longer plates. These will be the connection points for the two "loop wires" coming up from the pan.