What key points should I put into consideration when writing a WBS (work breakdown structure), considering that I have to read through a 1500 page BUCs (Business use case) and SUCs (System use cases) and a timeline of 3 weeks?

I have some questions about component diagram:1. How can I recognize components of a system?2. How can I recognize interfaces of a component?3. How can I know whether I should use Ports or not?