There seems to be a series of typos here but I can't work out what they should mean...
Placing one piece: Players place one of their pieces on an empty space on the board that is adjacent to one or more pieces of their opponent. In the diagram below, any empty space with the letters x, y or z may
not have a White piece placed on it. The White player may place a piece on any of spaces with an x on them, because the spaces adjacent to the Black piece on A1 (marked with a 1). The White player also may not be place a piece on any of spaces with a y on them, because the spaces are empty and adjacent to the Black piece on C4 (marked with a 2), or the z space (next to the unnumbered Black piece).
Sentence 1 says: "place one of their pieces ... adjacent to one or more pieces of their opponent"
Sentence 2 says the marked spaces (all the ones adjacent to one or more pieces of their opponent) may not have a piece placed on it.
Sentence 3 and 4 similarly flip flop in their sense...
So what is the correct rule?