I get asked frequently 'how do I get started', and I usually say 'read the manual', but I'll give this a shot.
Here's a short walk through of how to get started using eConnect
First of all, understand that there are two ways to code eConnect. You can just use what I call the 'direct' method, or you can 'serialize'. I'm not going to get into serialization here, because it's a lot more complicated, but it involves instantiating eConnect objects, then populating them, then sending the object itself to eConnect. The advantage to using serialization is that eConnect does some checking and validation for you along the way and will solve some issues earlier. It will also prepopulate a lot of default values.
Lately I've been using the 'direct' method, because it's simpler and I can code it quicker. So, here goes.