How to run a procedure on trigger on start of the project?

The built-in function called RunGlobalProcedureOnTrigger() is a client-side (i.e., Viewer) function.  It is a no-op when called from a server-side task.  You said, you wanted to call your VBScript procedure called main() at startup, then every time the tag called Clock5Sec changes.  If you want to call main() when the project starts, then you would do that in the VBScript task Startup Script.  If you want to call it again every time the tag called Clock5Sec changes, then I would suggest you do it in the Scheduler like this,

or like this,

Thanks Larry, I finally got the first solution. Great!

Thanks Larry, I finally got the first solution. Great!