Sending to Amazon- shipping label and FBA label

First time selling on Amazon and doing FBA for my first product. I’ve sat here for 2 1/2 hours watching videos, reading forums and articles but I can’t figure this out.

I got an FBA label from Amazon and my last step is to submit a tracking number. Now I’ve been selling on eBay for years so I know what a postage label looks like. And the FBA label doesn’t look like a postage label…. But that’s what I’m confused by.

Do I pay for my own postage label at the post office and then upload that tracking number? Or is that FBA label my postage label… but what’s the tracking number then? So the box should have two labels? That FBA label and a regular postage label? This is all super confusing for me and I appreciate the help.