I am confused how to calculate accumulated depreciation

Tuna Programming is owned by Mark Kosak and provides computer solutions to the hospitality industry. At the end of August 2021, they had the following adjustments.

Aug 31	Interest of $480 had accrued on the bank loan.
Aug 31	The balance of prepaid insurance is for a 4-month policy, one month of insurance has been used.
Aug 31	During August, Tuna Programming earned $520 of unearned revenue.
Aug 31	The computers were purchased on August 1, 2021 and have an expected useful life of five years, after which they will have no residual value. Record depreciation for August

Required

Using the following trial balance, complete the adjustments and the adjusted trial balance in the worksheet.

Do not enter dollar signs or commas in the input boxes.

Tuna Programming Worksheet August 31, 2021
	Unadjusted Trial Balance		Adjustments		Adjusted Trial Balance
Account	DR	CR	DR	CR	DR	CR
Cash	5,300		Answer	Answer	Answer	Answer
Accounts Receivable	2,750		Answer	Answer	Answer	Answer
Prepaid Insurance	5,200		Answer	Answer	Answer	Answer
Computers	13,800		Answer	Answer	Answer	Answer
Accumulated Depreciation-Computers			Answer	Answer	Answer	Answer
Accounts Payable		2,400	Answer	Answer	Answer	Answer
Interest Payable			Answer	Answer	Answer	Answer
Unearned Revenue		1,800	Answer	Answer	Answer	Answer
Bank Loan		2,860	Answer	Answer	Answer	Answer
Kosak, Capital		16,890	Answer	Answer	Answer	Answer
Kosak, Withdrawals	1,420		Answer	Answer	Answer	Answer
Service Revenue		5,700	Answer	Answer	Answer	Answer
Depreciation Expense			Answer	Answer	Answer	Answer
Insurance Expense			Answer	Answer	Answer	Answer
Interest Expense			Answer	Answer	Answer	Answer
Rent Expense	900		Answer	Answer	Answer	Answer
Telephone Expense	280		Answer	Answer	Answer	Answer
Total	29,650	29,650	Answer	Answer	Answer	Answer