How do I enter business expenses, Office rent and personal assistant? I receive T4A commissions but I can only enter employment expenses. T4A is not transferred to T2125

When you enter the T4A under box 20 for self-employed it will transfer to the statement of business or professional activities for commission income.  When you select self-employed you will say you received business, professional or commission income and when you indicate commission income it will transfer to the T2125 form where you will enter your expenses