Diagram 1, The lecture continues from previous Attack and Defense 1 (after joseki). Black invades and White has to answer.
Diagram 2, If White replies move-2, Black connects with move-3. White is not happy.
Diagram 3, If White continues to make living with move-6, Black can start attacking White with move-7.
Diagram 4, White move-1 is correct, then, Black move-3 is strong. White has to answer correctly here.
Diagram 5, White replies move-3, Black move-4 helps White to secure the land. White is very happy.
Diagram 6, Black move-4 here is correct, White cannot gets nice result and ended gote move-9.
Diagram 7, If White tries to fight back with move-2, White is basically destroyed after Black move-9. If White continues A, Black continues B too good for Black.
Diagram 8, White move-1 seems to be good move, Black takes the corner stone at move-2 and White settled its shape with move-3. This is reference from old joseki said to be acceptable by both.
Diagram 9, Black move-2 seems odd but Black cuts at move-4 is very strong, White has difficulty defending it; White has C and D defend but both leave aji for Black to manipulate. Black B is severe to continue attacking White. White is very unhappy due to the fact that Black does not spend extra move at A to kill the corner stone.
Diagram 10, White choses move-1 to kill the two black stones instead of move-5 from Diagram 9 does not guarantee good outcome for White as well.
Diagram 11, White move-1 is the only correct answer. Please take moment to appreciate this move.
Diagram 12, Black move-2 and if White cuts at move-3. White will not be doing well.
Diagram 13, If White tries to live in the corner move-5 to move-11. Black can start destroying White outside with move-12.
Diagram 14, White move-1 wedge is the only correct answer, even though the shape looks awkward.
Diagram 15, White sacrifice the stone with move-3 and create a great shape with move-5. Black move-6 to create eye and enough liberty but ended up with a heavy KO fight when White move-11 tesuji.
Diagram 16, Black could chose to move-1 here instead of move-6 from Diagram 15 to lighten the KO fight.