Save the notebook in some shared area that your students can access. For example, you could save it in with your other course materials on Angel or on the WWW.
To make a notebook available to someone other than your students, simply save it in a place where those people can access it (for example, your home page on the web) or convey it to them in any other manner (e.g. by email).
Students (or whoever has access to the notebook at the place you saved it) can then download the notebook to their own laptop and open it with DyKnow. This assumes that they have installed the (free) DyKnow client on their laptop per these instructions. [FIX LINK]
After someone downloads your saved notebook, it is theirs to mark up as they see fit, just like any other file.
Students who join your DyKnow class when it is in session should save their own notebooks (with their own private notes and other marks) at the end of the session. That way, they have their own, personalized version of what happened during the session.