SCVO have a very comprehensive section on their web site around Finance and Business Management, it includes access to a finance module on their Scope E-Learning platform. It provides information on three key aspects of financial management; systems and procedures, budgeting and tax and trading.
NCVO also have useful information on their web site around Financial Management.
Community Accounting Plus provide free financial tools and webinars and work mainly with charities and CIC's.
This is a basic template for planning the running costs of your community building.