You can use the Find (little magnifying glass) and type in "investment". Then highlight "Investment Expenses" and click Go. Put a checkmark beside which deduction best applies to you, Interest paid to earn interest, dividend and royalty incomeor  Investment management and advice (includes carrying charges), and continue to the page that applies.

You can also access this section by going to the sidebar of TurboTax, and click on Income > Investment Expenses.