First, you'll need to go to https://apps.twitter.com, and click on the Create New App button at the top. Shown here is my own apps.twitter.com page (you can see I already have a custom OAuth development environment that I tend to use for a lot of my projects that need to implement OAuth). We're going to start from scratch instead of using my pre-existing configuration, so we'll click on that Create New App button!:
This will bring us to the Create an application screen, where it will ask us for some information. Most of this is just the information that will be displayed in the Authorize this application ...