Need help understanding General Overhead rate and Direct Expense rate.

I am trying to determine if i should move forward with an overhead audit. I am trying to determine for formulas for the following items: general overhead rate combined overhead rate and direct expense rate I have obtained the following information from my accounting software: direct labor cost,indirect labor cost, indirect cost, direct cost. I just want someone to provide the formulas (general overhead rate, combinded overhead rate, and direct expense rate) using the direct and indirect items listed above. Also we have to use AASHOT Uniform Audit and accounting guide and the Florida reimbursement audit guide. But I really need Information Today!