Item 24E can be found under "Income > Other"  in the Individual Tax Return form.

What is Item 24E?
This item relates to tax withheld on lump sum payments in arrears. These arrears are back payments for periods older than 12 months. 

Essential Information:
  • The calculation of tax withheld involves the ATO’s Schedule 5 tax tables and prescribed withholding methods.
  • These payments must be reported according to the year of accrual (the year to which the arrears relate) for year-end reporting.
  • However, withholding tax is calculated at the time the payment is made.
  • This approach ensures proper withholding for large backdated lump sum payments without distorting the tax payable for the year in which the payment is received.

Learn more from the ATO on lump sum payments in arrears tax offsets here:
https://www.ato.gov.au/Individuals/Income-and-deductions/Offsets-and-rebates/Lump-sum-payments-in-arrears-tax-offsets/#:~:text=Lump%20sum%20payments%20in%20arrears%20(LSPIA)%20are%20taxable%20in%20the,relates%20to%20earlier%20income%20years