How do I split a deposit that has already been added (from my bank account) to my chart of accounts?

It's nice to see you here today, @samsandmireidaho. 

Let's go to the account's register so you can split a downloaded bank deposit. Please take note of the total deposit amount before performing the steps below. 

1. Go to Accounting from the left menu. 
2. Select Chart of Accounts. 
3. Locate the account and click View register from the Action column. 
4. Click the Filter icon. 
5. Choose Deposit as the Transaction Type.
6. Hit Apply. 
7. Find the deposit and click Edit. 
8. In the Add funds to this deposit section, choose the appropriate accounts, enter their description, and their split amounts.
9. Make sure the Other funds total figure matches your original total deposit amount. 
10. Click Save and close. 

The screenshots below show you the steps. For detailed instructions, check out this article: Enter A Split Transaction Into The Register. 

Once done, there will be a Split status on the deposit. See the screenshot below for your visual reference. 

As always, you can run the Transaction List with Splits report in the program. This lets you view all your split transactions within a specific period, such as your split deposits. Just go to Reports from the left menu. Then, enter the report name in the Search box as seen in the screenshot below. 

I'm just a comment away if there's anything else you need. Have a good day, @samsandmireidaho.