The Staged Delivery Plan is a description of all features that will be included in each release. Each feature needs to be precisely described. Ideally, it will refer to a requirement number from the specification document. However, if you didn't number your requirements, then you have to explain them with narrative.
If a feature is going to be partially implemented, you need to describe the character of the functionality you plan to implement. One of the most common sources of confusion on student projects is uncertainty about whether a certain feature is supposed to be working yet. It is the job of this document, along with the Integration Plan, to eliminate that confusion.
Staged Delivery is discussed throughout the McConnell text and a simplistic example is shown on page 165. Benefits of Staged Delivery are: