Hi there @Kelsie504,
You'll add the transaction if it doesn't exist in the register, use find match when it's already in your register.
In your case, verify if it's a duplicate transaction. Once verified, you can delete the other one to fix this. Please see this article for details: Categorize and match online bank transactions in QuickBooks Online.
You can also visit our page about banking and bank feeds for more tips and recommendations.
Should you have other questions about banking, please let me know. I'll be around to assist you. Thanks for jumping in and have a great weekend.