Here's some general new seller info for you, including info on how to get started.
New sellers are targets for scammers that will make fake offers and try to get you to text or email them outside of eBay. Using fixed price listings with immediate payment required will cut down (but not eliminate) the number of those scam attempts. Keep messaging on eBay and don't fall for attempts to get you to change the shipping address, or claims the buyer cannot pay saying you need to click some kind of link or contact them off eBay to make payment work. If you have any more questions come back and ask.
Getting started:
https://www.ebay.com/help/selling/getting-started-selling
Selling limits:
https://www.ebay.com/help/selling/listings/selling-limits?id=4107
Selling fees:
https://www.ebay.com/help/selling/fees-credits-invoices/selling-fees?id=4822
Payment holds for new sellers:
https://www.ebay.com/help/selling/getting-paid/getting-paid-items-youve-sold/payments-hold?id=4816
General payments info:
https://www.ebay.com/help/selling/getting-paid/getting-paid-items-youve-sold?id=4814
Shipping basics:
https://www.ebay.com/sellercenter/shipping
Optimizing listings:
https://www.ebay.com/sellercenter/listings/listing-best-practices
