Despite it was pusblished in 1993, the second chapter contains all the fundamentals about the Neuron model and Network achitecture, includind on layer models and multiple layer networks.
It is very useful to introduce using the Neural Network toolbox of matlab because it simplifies a lot of internal issues related to the implementation.
There are also some examples (view the link) that can help you understand basic concepts.
In
Fabrício P. Härter, Haroldo Fraga de Campos Velho, New approach to applying neural network in nonlinear dynamic model, Applied Mathematical Modelling, Volume 32, Issue 12, December 2008, Pages 2621-2633,
an example of application for data assimilation purposes is included. You may find how they choose the number of neurons as well as a justification of using multilayer neural network.