To add a new story to product backlog,
1. Click on Add Story button.
2. On click, quick add drop down asking for details will open.
3. User needs to select story type that can be story, epic, spike, defect etc. User can give appropriate name to story and estimate the story.
4. If you want you can save the story or else you can add with more details.
5. To add the story with more details click on Add with Details.
6. On click of Create, the user story will be created and then you can change other details in that User Story.
7. Once user story is created, you can change other story details and click on Save & Close.
There are two other options available in Save story,
1. Save Changes: The user story will be saved but the edit story popup will be kept opened.
2. Add New: Opens new Add with details popup and allows user to create new story.