Puzzle 1 — Black to move: white's row-5 three is open and screaming, but black's row-8 three is capped only on the left, and (8,8) turns it into a rush four. The four that saves the game: it forces white to (9,8) before white's three can grow a step, and only then do you cap the row-5 three at leisure. Answering threats in the wrong order loses; your own forcing move buys the right order.
Finish this step to move on.