This is the main documentation for Bow Simulator. It gives you an overview of the program features, explains all input parameters and simulation results and contains some additional background information.
The Technical Documentation is still a work in progress and is intended for developers and interested users. It covers the theoretical and technical details behind the software like e.g. the mathematical bow model, the derivation of the equations of motion and the numerical solution methods.
Simulations can be used to evaluate specific bow designs, but they don't really tell you how to design a good bow. If you want to learn about bow design you could have a look at the following sources:
The Traditional Bowyer's Bible, Volume 1, Chapter 3: Bow Design and Performance by Tim Baker. All the common design choices and their performance implications are explained in a very practical and understandable way.
The article on bow design from the crossbow building wiki is also a good read. It is of course geared towards crossbows but most of it also applies to bows in general.
SuperTiller is an Excel spreadsheet made by Alan Case for simulating the statics of user-defined bows. It's probably one of the most well-known bow design tools.
Woodbear's Selfbow Design Sheet [zip] by David Dewey is an Excel spreadsheet that calculates the necessary dimensions for a bow according to a user-defined stress distribution.
BowCAD by Joachim Gröger and Chris Goetz was a commercial attempt at bow design software. At one point they were even offering different kinds of licenses on their website http://www.bowcad.com/. Unfortunately it seems to be no longer available.
DrawCurve Calculator by Chris Snyder is a utility program for visualizing a bow's draw curve and calculating the stored energy.
x-Ballistics is a browser based application that can simulate the exterior ballistics/trajectory of arrows.