can you explain how to do the substantive test about the key assertion of the following risky account, and how to do the audit procedures.

1. sales revenue: occurrence, cut-off,accuracy,completeness and classification
2. accounts receivable: existence, valuation and allocation
3. cash: existence, valuation and allocation
4. PPE: existence, valuation and allocation
5. Inventory: existence, valuation and allocation
6. Accounts payable
7. Expense
8. Debts(loan)