To instantiate (i.e. create an instance of) an ActiveX object, you first need to declare a variable of type object, or of type class. Then you just call the built-in function CreateObject. The built-in function CreateObject takes as an argument a string expression that evaluates to the name of the ActiveX object type you want to instantiate. See the Irie Pascal Programmer's Reference Manual (in "progref.html") for more information.
NOTE: After you have finished using the ActiveX object make sure you get rid of it (see disposing of ActiveX objects).