Look in your Paypal account.
You will see if it has been accepted by the seller.
Many eBay sellers are somewhere between Mom&Pop shops and hobbyists.
Those may not see your payment for several hours.
Some may not use Paypal labels, which automatically send you notice when a shipping label is printed.
Some leave feedback (which is completely voluntary) in batches, only when they are sure the customer is happy.
Allow 48 hours, then use eBay Messages/Contact Seller to ask for the date of shipment, service used and the tracking number.
The tracking number is not actually useful to you, except as a confirmation of shipping. It is required in some forms of Seller Protection.
Many seller don't use expensive tracked services.
