There are two manuals here. One relates directly to the single financial modelling file "Model All" and provides a detailed explanation of the file and its operations.
The other covers the broader Financial Modelling - Renewal Gap Program which expands upon the single financial modelling file and enables you to present your modelling results in a far more flexible way. There are currently 2 versions of the manual here. The N2 which was released in late 2009 and the N3 released in April 2012 and updated in Feb 2013
The General Assets Module handles all assets that are not specifically covered by other asset modules
Roads Asset Management Module Manual