Often the best way to learn table tennis is to watch a top player and mimic what you see. Pick out someone whose game or strokes you like (or ask a coach to suggest someone to watch), and just watch how they do their shots. Then copy them by shadow-practicing (practicing your stroke without the ball) until you can the shot as well as that player . . . at least without the ball. Then find a coach or practice partner and practice the shot until you CAN do it as well as the player you were copying.
Feel free to ask the player if you have any questions on how he does it. Most players are glad to help out – and since many top players spend many hours every day thinking about their game, they may be just dying to talk about it! You should also have a coach see how you are doing to really hone the technique.
Try watching a top player just before you play a match. You'll be amazed at how much better you can do the shot in a game if you first watch someone else doing it really well. In table tennis, it's often monkey see, monkey do!