This is the correct solution, but you don't get full credit (since you went wrong before, or used the 'show solution', 'undo' or 'try variation' feature).
This is wrong. (If this move is not even in the SGF file, then the "wrong" sign and the stone you played will disappear after a short time, and you can try again. Otherwise, this is shown at the end of the wrong variation; this means that you possibly went wrong earlier - use 'undo' to go back, or 'show solution' to see the solution.
The green labels show the correct moves, the red labels show the wrong moves. If it's the opponent's turn, all variations are shown with blue labels. (Black to kill in this problem).