As far as framing a dormer goes...I would not suggest that a novice DIYer attempt to perform such a project without some sort of onsite experienced supervision. This involves structural framing and structural support during the work process. You will need to obtain a building permit which will require a diagram showing how the dormer(s) will be structurally built.
Needless to say, here are examples of Dormer "framing". These are examples of two kinds of dormers, shed-dormer and gable-roof dormer.
Shed Dormer construction:
Gable Roof Dormer construction: