The declaration is pretty straightforward. You can read the full text here.
It boils down to five simple principles.

Expression: Don't censor the Internet.
Access: Promote universal access to fast and affordable networks.
Openness: Keep the Internet an open network where everyone is free to connect, communicate, write, read, watch, speak, listen, learn, create and innovate.
Innovation: Protect the freedom to innovate and create without permission. Don’t block new technologies, and don’t punish innovators for their users' actions.
Privacy: Protect privacy and defend everyone’s ability to control how their data and devices are used.Organizations can add their support to the Declaration here. Individuals can add their support on the action pages from Access, ACLU, CREDO, EFF or Free Press.