You're welcome, and I'm glad to have you aboard!
Here is a link to a post I made with instructions for new players. It is a bit dated, but most of it is accurate. You'll need to choose one or more characters. The new characters in the Gold section are your best bet to start with, as they have the least catching up required. There were nine, but two of them are now dead, leaving seven. You can choose only one of them, but you'll be able to select more characters from the other sections if you wish once you've caught up on their stories.
This thread has more information on the game in general, including a link to the above post. The second page has more recent posts concerning Chapter 4.