This episode is about sharing the right side. It ends with a very big mistake by Black. Actually, every move here is wrong. I think that reading this is very instructive because it could help avoid similar mistakes in future.
White 1: Bad. I constantly repeat to myself that moves like this should not be played automatically. The points a and 5 should be considered as well. These are points and they add up. At a was the best move locally. It makes Black crawling along the line gote, and White will not have to worry about the possibility of ko.
Black 2: Bad. The best move locally is b. This is discussed in stupid moves.
White 3: Natural connection. Good at least locally.
Black 4: Sente. Locally good.
White 5. Bad. White avoids a possible ko. I don't think that this luxury is affordable. White is behind.
Black 6: Bad. Leaves a hole behind.
White 7: Bad. White had to play at c and cut Black's stone off.
Black 8: Bad. It just strengthens White. At c was a good move threatening to save the stones.
White 9: Natural connection.
Black 10: An awful mistake that allowed White to cut at c.