If you sold over $20k in 2019, Amazon should have emailed you about a 1099 sometime in January. More about this here: https://sellercentral.amazon.com/gp/help/help.html?itemID=200663290&language=en-US&ref=mpbc_200663310_cont_200663290
You can access your 1099 by going to your Seller Central account. From the Reports tab, select Tax Document Library. In the section titled IRS Forms Issued by Amazon, click the link under Action in the 2019 row to download your IRS 1099-K Form.
I believe the 1099 will show your total revenue. From there, you would need to deduct AMZ fees, inventory costs, and other business expenses (home office, phone, laptop, biz travel, etc.).
The easiest way to do all of this would be by using a software like Inventory Labs that will pull all of your fees from Amazon, you then input your product cost and it will generate a 2019 P&L. You should be able to just sign up for the free trial with Invneotry Labs to generate and download a Profit & Loss. Link: https://www.inventorylab.com/
Hope this helps. Please keep in mind that we're not tax experts and I a personally pay a CPA to do my business and personal taxes for me :)
