How do I enter a credit card charge

Use the Expense entry screen and select your already created credit card type account as source (or add new)

To create an expense rather than a cheque click +, and under Vendor/Supplier, Expense

If you have a cc return or get cash back you enter those under the very bottom choice, Credit Card Credit (if you use that to enter charges everything will be upside down and backwards)

If you used QB desktop in the past you are familiar with a separate cc entry screen under the banking menu