The tool will never automatically withdraw funds from a 529 account, you'll need to enter those in the Expenses and Healthcare section
Follow these steps to account for educational expenses in your plan:
Step 1: Go to My Plan > Expenses
Step 2: Navigate to One-Time Expenses
Step 3: Press "Add a One-Time Expense +"
Step 4: Indicate the amount in future dollars
Step 5: If you plan to pay over a period of time select "annually and select the appropriate start and stop dates"
Step 5: Select your 529 as the source account
Step 6: Enter the age the primary planner will be when you expect the expense to occur.
Step 7: Don't forget to press "Save" when complete
Withdrawals from 529 plans are tax deductible by default
