Paypal credits for sold items are not appearing in my bank account

I am relatively new to ebay and PayPal. I have been buying and selling for two months now and assumed that monies received for sold items would appear as credits in my registered bank account. Debits for some items I bought have appeared, but not all of them. How do I get all my PayPal transactions to come from and to my bank account?

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Orignal From: Paypal credits for sold items are not appearing in my bank account