Yes, you will need to amend to report this Form 1099-K on your return.
The first step is wait for your original return to be fully processed. That means waiting until you get your refund, or at least 21 days if you owe taxes.
Once you are ready to amend your return:
If you file a state return, you can continue into your state after your federal return is complete.
Sorry but I have desktop so when I sign into Turbotax online my tax returns are not there. Is there something I can do to add to my online account or do it from my desktop version?
As soon as you open TurboTax without a File name, the first screen presents the opportunity to amend.
You can't use TurboTax Online.