Hello, I am really interested in your project. I am experienced BA, worked for many years for IT project. I did similar job for many client. I can create BRD with necessary elements, like: requirements analysis, use cases diagrams and analysis, processes swim line BPMN flow charts, web site map and wireframes. Please check portfolio section of my freelancer profile to see examples of my work: https://www.freelancer.com/u/ddemidczyk?w=f.
Please feel free to message me so we can discuss details of your project. I will be happy to dedicate my knowledge, experience and time for your project.