Accrual vs Cash accounting

Having some trouble working through this case study and hoping for some insight. The case study is about a medical practice that recently switched management and is now getting mixed results in their accounting sheets.

Case Study is attached along with the relevant financial documents. The questions I need help with are visable in the last image. I only need help with question #1a and #3a,b,c

Incase questions are not visable they are:

1) Discuss the differences in the Financial Statements and the effect that these differences have on the Revenues and Receivables.

2) Recompute the Income Statement and Balance Sheet provided by PMI on December 31, 2011 to make the two years comparable.

3) Recalculate the Statement of Cash Flows provided by PMI for December 31, 2011 using the recalculated Income Statement and Balance Sheet as well as the correct beginning account balances.

4) Discuss the differences between the Statement of Cash Flows provided by PMI and the Statement of Cash Flows prepared by you.