You are going to need to set up a bunch of items and accounts in QuickBooks Online.
First, of course, all of your inventory parts (products) must be set up with both Sku & name.
Next you will need to set up the items that map to the various Amazon fees and other items like the reserve.
For each of these Amazon items, based on how you chose to set up your Amazon Fee Mapping, you will need an account in the chart of accounts. I like to put most of these in Cost of Goods Sold (COGS). The exceptions would be the reserve, and Amazon Capital (if applicable).
Other exceptions would include things like Gift Wrap and Gift Wrap Chargebacks. Those will go in the income section, perhaps included as sub-accounts of something like, “Other Amazon Charges Collected.”
Once all of this is set up, you will be ready to run your first Amazon Settlement Report Import.