QTP supports both client server and Web applications. Does it support Plug-in?

Hi All, I am 4 yrs experieced in manual testing and new to automation tool QTP. Iam trying to learn it thru online and material i have.I am able to understand but unable to trace out which method or function to be used where necessary in VB Script. How come we know the functions or methods to be used to open a window when clicking on button or so...Pls suggest me.How can i proceed further to apt VB Script.