1. Start with what a contra-asset means. Most asset accounts carry a debit balance and go up when the business gains value. A contra-asset account does the opposite: it carries a credit balance and exists specifically to reduce another account it's paired with. Accumulated Depreciation is the most common example a small business will ever run into.
2. Know where it sits in the chart of accounts. Create it as a Fixed Assets type account with detail type Accumulated Depreciation. There's no dedicated contra-asset category in QuickBooks' account-type dropdown; this detail type is how the contra behavior gets built into the Fixed Assets type instead.
3. Set it up as a sub-account of the asset it offsets. Most businesses nest Accumulated Depreciation under the specific fixed asset it tracks, Accumulated Depreciation: Vehicles under the Vehicles asset, for example, so the Balance Sheet shows the asset's cost and its accumulated depreciation stacked together, netting to book value right where a reader expects to see it.
4. Understand what the balance actually represents. It's a running total, not a single period's number. Each period's depreciation entry adds to the existing balance; it doesn't reset. A vehicle bought three years ago has three years of depreciation stacked in that account, not just the most recent entry.
5. Watch how it interacts with the asset at disposal. When a fixed asset is sold, scrapped, or retired, both the original asset account and its accumulated depreciation need to be cleared out together, along with recording any gain or loss on the difference between book value and whatever, if anything, the asset sold for.
6. Expect it on the Balance Sheet, not the P&L. Accumulated Depreciation lives entirely on the Balance Sheet, netted against its fixed asset. Depreciation Expense, the account it's paired with when a depreciation entry posts, is what shows up on the P&L instead; the two accounts work together but report in different places.