Iam stuck with the Project rules

I want an global project with tasks which all members can access it but only can VIEW the project. They are not allowed to EDIT any of the task or Time lines. Only the Manager who created this project is allowed to change this project and his tasks. This projects is just for an complete Overview maintained by one person but viewed by all members.

How can i set the rules in SECURITY --> RECORD RULES ?/

Any HELP would be grateful !