PLL parity: two diagonal corners swapped
Step 1 / 22
r2: Right inner layer: turn 180° (Written as TR2 in the textbook)
Every edge is in place. Only the front right and back left corners of the top layer have swapped.
The swapped corners at the front right and back left. Do PLL parity, then the Na perm from PLL: diagonal corner swaps.
Step 1 of 22: r2. Right inner layer: turn 180°