Tap 3 Mahjong is triple-match rather than pair-match: you tap tiles to move them into a collection row at the bottom, and three of a kind there disappear.
The row's size limit is the whole game. Fill it without completing a match and you're finished, so each tap is a bet that you'll find the other two.
It's triple-match: you collect tiles into a limited row and any three matching clear, rather than removing pairs directly from the board.
By filling the collection row without completing a set of three. Keeping free slots as a buffer is the main defence.
Yes — tap tiles to collect. Nothing to install.