Prati,

If you already got the job then you must have the background and experience they are looking for, so rest easy.  My advice to you is to continue to learn.  Read books, ask (specific) questions to seasoned professionals in community and keep expanding your knowledge.

But keep this in mind, the biggest problem that most business analysts have is trying to do what they THINK business analyst need to do because some methodology or template says they should.  Methodologies, analysis best practices, tools, templates: these can be helpful but they are not everything. Use common sense and do what makes sense.  Anytime you plan to apply some analysis process or task ask yourself why it's important. Ask yourself, what is the risk to the project if I DON'T do this task.  Understanding the WHY behind the work you are doing is more important that checking off steps in a list or fields in a template.