Accounts in Manage can be mapped to Sub-accounts in QuickBooks Online simply by delimiting the account in Manage with a colon “:”. QuickBooks Online supports sub-accounts up to 5 levels deep. An account 5 levels deep in Manage would then be in the format “level1:level2:level3:level4:level5”. Do not include the Account Number.
Since the Account Number field is optional, QuickBooks Online uses the Account Name as the primary key. As a result, the Account Number should never be included in any mappings within Manage.