Even though the question is with JBehave, I think cucumber provides better documentation and will help you understand Gherkins better.
Your scenarios should describe the intended behaviour of the system,
not the implementation. In other words, it should describe what, not
so instead of :
he clicks the first item
user logins to portal
Adds item to cart
Checkouts and makes the payment
The actual implementation is hidden in the step definition.
The user logins to portal actually reuses the functions to enter password ,click login etc , in the step definition.
Hide the implementation details in step definition and in feature file use only the process.
In your case add step like ,
user completes the prerequeiste tasks
add use it to wrap the actual 490 steps inside step-definition:
Running step before each story:
If you want to run this step before each story, then use before (if using jbehave syntax)
else use Background (If using Gherkin syntax)
Read more at: