First-layer corners
The white corners go above their slot and drop in with the trigger.
First-layer corners
Turn the cube over, so the cross is on the bottom and yellow on top. Bring a corner with white on it above the slot it belongs in, with its edge beside it, then insert the pair with `U R U' R'`. A corner that arrives split from its edge needs the same trigger to bring them together first, and a twisted corner needs another look: the trigger turns it as it goes in.
A corner and its edge sitting above the front-right slot.
Checked by the engine: F2L 1
F R' F' R