You can chose two ways to pronounce your name in Japanese.
One is, to let people read it as it sound in your language (Chinese.)
汪=ワン
慧=フイ
珊=シャン
Above is spelled in Katakana letters (which is used for foreign words) and it sounds close to your name, "wang" "hui" "shan".
Another way is, to use Japanese pronouciation of Chinese chalacters.
Actually, this is more common among the Chinese people living in Japan.
The characters of your name are pronounced as follows in Japanese.
汪=ou (sounds like, oh in English)
慧=kei
珊=san
In hiragana, it is spelled as follows.
I think you use Hiragana than Katakana in this case, because the Chinese characters are pronounced in Japanese way.
汪=おう
慧=けい
珊=さん
But just for your information, in Katakana, it is spelled as follows.
汪=オウ
慧=ケイ
珊=サン
Good luck and make many friends in Japan!