For each settlement you receive from Amazon, Link My Books creates a journal entry.
Since journal entries need to balance debits and credits, they can't be left with the balance of the settlement as a total - the amount must be also allocated to an account so that the journal entry can balance to zero.
If the balance of a settlement is negative then Amazon will charge your card on file.
If the balance of a settlement is positive then Amazon will deposit the funds into your chosen bank account.
In order for us to know where to allocate these charges and deposits we need to know which bank account and credit card you have on file for each of the marketplaces you sell in.
During your initial account set up or on the QuickBooks Bank Accounts settings page, you can select these accounts, as shown below: