Hello huiying ong and welcome to the Tableau Communities;
Before we get to your question, just a note that Tableau Forums is generally the best place to ask procedural questions like this. The Viz area is typically used for challenges and to discuss the pros/cons of a user's visualization.
I highly recommend you go to the Forum area and SEARCH for your answer there-- you'll find many others have posed the same question. This, for example, may be helpful:
If you don't find what you need there, try posting in Forums: many more people frequent that area and will be happy to lend a hand.
Remember: if a response has been helpful, don't forget to hit "Mark as Helpful" or "Mark as Correct" if it has answered your question.
Good Luck! --Michael