Would someone please explain the difference?
Storyboard is a visual representation of how the product is used. You can imagine it as a comic, that shows the user, the context, and how they use the product in that context. The storyboard makes it easier to imagine the product in the users' hands. We use it to circulate different ideas, use cases or problems within the team.
Customer Journey is a tool to look at the big picture. It maps the whole experience of a customer, from the first time they hear about your product until they use it, and even after the usage. We use this tool, to put the product in context and think about what features it needs.
User Journey is the flow users goes through while they user your product. Usually we design user journeys for the most important user goals, and map how will people achieve these goals. The best is to design the ideal journey. The user journey helps us to think in processes instead of standalone screens while we design the product. We can also use the user journey map to discuss different feelings and thoughts the users will have, so later we can reflect to them on the design. The user journey itself is a diagram, that doesn’t have any screens on them, just boxes and the information we gather. We create user journeys before we start designing screens to ideate on different routes and find the one that fits the user needs.
You can read much more about user journey design in my blog post, where I show you some real-life examples, and also provide useful tips on how to do it:
User flow is very similar to user journeys, but it is more like a flow chart. Unlike user journeys, user flows show the screen UI or wireframe of each step. It can help to look through the process, and it is also a good tool to show developers how the product works. User flows usually highlight the clickable areas and connect them to the next screen design that shows what happens if we click there.
Your using different terms in your subject question and your decsription. I'll very briefly state all three definitions, "Storyboard", "User Story" and "User Journey".
It's a graphical representation of how your web app / video / or anime piece will play out. Visually showing what, when and how it happens.
This is a concise decsription from the perspective of the user of how they will achieve a particular task. For example; "As a 'type of user', I want 'some goal' so that 'some reason'."
This is a described series of steps that show how a typical user would interact with the web app that is being designed.
How a User Story is Different from a User Journey
Again this does depend on the context of it's usage but a User Story in my experience is based on a specific user, so this could cater for a particular type of user to answer a specific problem whereas a User Journey can be a random user that may use the web app. This also includes Dynamic Usey Journey Scenarios.
Note: Based on context, a User Journey and Story can be one and the same.
User Stories: http://www.mountaingoatsoftware.com/agile/user-stories