Forgot a few minor things about packaging for use inside other projects 😀. Should be good now though.

src/index.ts

@@ -0,0 +1,15 @@
+import { API, APICredentials } from './API';
+import { Campaign } from './Campaign';
+import { Template } from './Template';
+import { Subscriber } from './Subscriber';
+import { List } from './List';
+
+
+export {
+    API,
+    APICredentials,
+    Campaign,
+    Template,
+    Subscriber,
+    List
+}