I sell handmade. I remember that sorting out the exemption was a bit of a headache, but I can't remember how it was resolved. Sorry, I know that's not helpful, but once it is sorted, adding stuff to the catalogue is pretty easy and straightforward. Be sure to set your handling times to something you're comfortable with. You can set them on each product, too, if some things take longer than others to make.

Consider registering a trademark and applying for Brand Registry. It gives you more tools and protection.

Then there's FBA (Fulfilled by Amazon) or FBM (Fulfilled by Merchant - You) I tried FBA and hated it. As JillyB said, so many metrics and things to consider. For example, you may start getting charged for 'aged' inventory that hasn't sold. I didn't need all the hassle. It felt like I was a slave to Amazon, rather than running my own business here. I find FBM much less stressful than FBA, but FBA might suit you.

As my stuff is hand-made and made to order, I shouldn't have to accept returns in most cases, but this is Amazon. Amazon will refund customers readily.

However, Amazon does have a large customer base, and it encourages growth (I find eBay very difficult to grow on as it's so stifling.) So there's money to be made here, but be prepared for the few chancers and scammers.