3D Images- parallel projection and perspective projections

I need help with parallel projections and perspective projections, this is what I have so far:

Vertex List

v X Y Z
v X Y Z
...

and Face List


f V1 V2 V3
f V3 V2 V1
....

I have a java application that reads in a vertex list and face list. I also have code to write 2-D lines and ouput that image file. In my code I have the standard 3D default values defined for: PRP and VRP reference points, VPN and VUP vectors, and VRC window coordinates.

What I need help with is understanding the algorithms of the parallel and perspective projection. I looked up the general theory of the matrix translations of these projections; however I have no text book or guide on the topic (and am completely new to graphics). So I really do not know where/how to get started.  I do not need code; I need something that would help me understand these projections and how these projections will help me take a vertex list/face list and translate that data in 2D lines. If I can understand the concepts I am pretty confident that I can code it.

Thank you for your assistance.