Question

How do I run a subprogram from a different class

Answer 1

Make sure that the method from another class is public.
If the target method is static - you can use OtherClass.OtherMethod(); to execute it.
If not - you have to create an object of this class, to have access to its methods:
OtherClass MyObj = new OtherClass();
MyObj.OtherMethod();