How can I link/apply vendor bills that were recorded as journal entries to the check that was written to pay those bills?

I'll walk you through applying the bills as journal entries to the check you've written in QuickBooks Online (QBO), @tmansfield617. 

First, let's run the Journal report to open the journal entries that you've recorded for the bills. Then, make sure you've selected a supplier in the two rows under the Name column. That way, the entries will display on the right side of the Check screen. I'll guide you how. 

1. Go to Reports from the left menu. 
2. Enter Journal in the Search box and select it. 
3. Set the Report period. 
4. Click the journal entry to open it. 
5. Verify the accounts and amounts in the Account, Debits (USD), and Credits (USD) columns. 
6. Be sure you've selected a supplier in the two rows under the Name column.
7. Click Save. 
8. Repeat the process for the other journal entries. 

The screenshot below shows you the fifth to seventh steps. 

Second, let's go to the check you've written and delete it. Then, recreate it so the system will trigger to display those journal entries in the Add to Check window. This way, you'll be able to apply them to the check to pay those bills. Here's how:

1. Go to Expenses from the left menu. 
2. Locate the check to open it. 
3. Click More and choose Delete. 
4. Go to the + New button from the left menu. 
5. Select Check under Vendors. 
6. Choose the same vendor with the journal entries in the Payee drop-down.
7. Click Add all in the Add to Check window. 
8. Review the journal entries and their amounts. 
9. Hit Save and close. 

View the screenshots below to show you the last four steps. For the detailed instructions, see the Pay your bills through checks section through this article: Entering And Paying Bills. 

Once done, I recommend running the Bills and Applied Payments report from the Reports menu. It lets you review the payments you’ve made, like your check and the bills that go with them. See the screenshot below for your visual reference. 

I'm here anytime you have other concerns. Take care always, @tmansfield617. 

Apologies for such a late response.  Many thanks as the steps you provided are clear and effective.  Thanks again.

Tim Mansfield