So I'm working on the current month (April) and it just so happens to be the year end as well. I was also provided with the Trial balance from the previous month (March).

My question is: Where do I include the information from the March Trial Balance in the April work sheet?

I've done all the unadjusted trial balance, adjusting entries, and adjust trial balance for the month of April. But I know that I will be needing the information from the month of March to do my closing entries.

Any advice?

Your account balances from March will be your beginning April balance. You will post your transaction in April to the appropriate accounts, then at the end of April you will prepare your trial balance to make sure your debits equals your credits.

Your Closing entries will be done after your financial statements are done for the year end. The closing entries involves closing out your income statement accounts to your balance sheet accounts.