After sifting through dozens of YouTube videos online about how to froth the milk with the default three-holes tip steam wand of La Pavoni, I gave up using the pre-installed steam tip and purchased a one hole tip from eBay as some people suggested on the home barista forum.
voilà , with this new one hole tip, I finally be able to steam the milk with the desired microfoam result, which is nicely float on top of the coffee (see picture below), and which is essential to make latte art. With the original three-holes tip, steam came out with three different directions, and it was very difficult to get the milk swirling. Next step is to how to make a rich microfoam.