Hello Ancy,
If you go to the help menu in the menus you will find the VBScript manual which has all of the function commands accessible to you. Additionally we have a webinar that looked at some of the VBScript functionality. Under the support drop down on this site you will see an option to watch webinars. I would suggest “OptiFDTD: Advanced Features” as it looks at some uses of the VBScripting capabilities.
Scott