Open Up Stories->My Novels. Click "Add New Novel".
Here you can write your novel title and a short description of it. You must select a Type and Genre.
Writing the author's notes is optional but it is highly recommended that you give your readers information on what you're expecting from crits and fill in gaps they might be having. These notes appear before and after all submissions in the novel.
The advantage of using these 'novel-global' author's notes is that you can change them here at any time and all your chapters are updated immediately.
Having author's notes here does not preclude having submission-specific author's notes as well. In fact, the two work very well together.
Once you're done click "Send".
Hide Novel
When you put your submissions into a novel, they become inherently more visible than they would be otherwise. For example, if you have a chapter in a public queue and then chapters in a private queue, readers are able to see that you have submitted the chapters in your private queue (even if they can't access it). Sometimes you might not want the novel to be visible at all. For example, if you are done and don't want any more crits.
You can then choose this option which will make the novel hidden to everyone but you. No one will be able to see the novel navigation on the submissions or the novel information bar.
Keep all discussion in a single thread in your forum
This can be a very powerful tool to help you consolidate discussion about your novel.
When people discuss your submissions a thread is created for each submission. If you are submitting a novel consisting of 10-20 submissions that can potentially mean a lot of threads and each submission typically only has a couple of replies. Therefore, it can be beneficial to collect all those messages in a single thread.
You can select this option at any time, whether you are creating your novel or editing it. However, once you select it the discussion threads for all your submissions in the novel will be moved to the novel thread and the process is not reversible. You should make sure this is really what you want before proceeding.
If you add new submissions to a novel where this is selected they will always allow discussion and that cannot be changed. If you add an existing submission to such a novel the discussion thread (if any) will be moved under the novel as well.
Optional Information for your readers
These are a set of fields which you can fill out if you want to give your readers some additional information about your novel. It is totally optional to add information here.