I have an example you can use, with a lot of illustrations, on the following website, free: http://planasyougo.com/example-initial-sales-forecast-for-a-restaurant/
That should give you at least an idea of how and where to start.
Tim Berry is the chairman of Eugene, Ore.-Palo Alto Software, which produces business-planning software. He founded Bplans.com and wrote The Plan-As-You-Go Business Plan, published by Entrepreneur Press. Berry is also a co-founder of HavePresence.com, a leader in a local angel-investment group and a judge of international business-plan competitions.