ayodayo

Accumulated depreciation is a contraasset account, it’s used for proper valuation of real assets; it’s the same for the allowance for doubtful accounts (receivables valuation). Debits and credits are about increasing and decreasing a given account. I think you should know how a debit or credit affects certain accounts.
Think of it this way: Debits on the left, Credits on the right.
Assets=Liabilities + Equity
Debits increase the left side of this equation. Credits increase the right side (debits on left, credits on right). Vice versa for decreases.