We're building a website to manage our company asset, and apply Agile/Scrum to this project. We started with the Product backlog as in attachment. We planned to start the first Sprint but the team concern about system requirement - things outside PB such as hardware/software architect, database design, security, user role/permission,.. They said without these requirement, they cannot start.

So, may questions are:

1. Our PB is a good one
2. Do we need to conduct System specification. If yes, how detail it needs and when to conduct it (before or after getting user story)?

I thank you very much.