You add a blog to the network when signing up but it should not be the blog you want to get backlinks for.
It's just a blog that you contribute to the network to receive posts from everyone elses sites.
Then, for doing that you get a quota of 250 posts per month which will go out to other peoples blogs.
You can include up to 3 keyword/backlinks in the articles that you submit into the system that can link back to your real website that you are trying to rank.
Indeed!
Matt, it is probably a good idea to create a whole new blog to plug-in to 1waylinks and use it mainly for accepting articles. The more blogs you add the more quota you get.