Aweber and Blog Broadcast

I recently signed up with Aweber, an awesome autoresponder and newsletter service. I have almost everything setup, except for the blog broadcast. I am actually not sure if I am going to use it, I am still doing some thinking. What it does, is that it sends a message to your list when you have posted something on your blog. You can send it automatically or manually. I tried to set it up and I did send one message to my list, but it didn´t go exactly as I planned. My list received an empty message, with no subject :-) I have looked for a way to understand the codes, somewhere that I can read some instructions on how to set it up, but so far I haven´t found it. At first it seemed like a two-minute job, but after I failed at first try, I am not sure if I dare to do it again without finding some instructions. It´s a great service, but a little harder than I thought to set it up.