Problem migrating data from old version 1Password on Mohave to new 1Password 7.7

SITUATION: I've been using 1Password Version 3.8 (I know, an old version). I recently upgraded my Mac OS to Mohave, and now the version of 1Password that I've been using won't work. I now know the sad fact that the old version of 1Password I've been using is not supported with Mohave and 3.8 won't function on my laptop now.

TO RESOLVE: I want to begin using the newest version of 1Password v7.7, and signed up for the 2 week free trial and will then be paying the monthly subscription.

DESIRED OUTCOME: Use 1Password v7.7 - and import the data that I had from the old version of 1Password I was previously using.

PROBLEM: I'm so far unable to migrate the data from v. 3.8 into v7.7.

STEPS I'VE ATTEMPTED AFTER READING HELP:

I understand from reading previous answers in the forum, that v7.7 uses OPVault instead of the old AgileKeychain vault format I'd be using with 1Password 3, but that I can import the data into my new vault after setting up the app. That I should just go to File > Import > 1Password Keychain.

• I see the agilekeychain Backup Data file from v3.8.22 on my Mac
• In v7.7 I click File > Import
• For "Where is your data coming from", I chose "1Password Keychain"
  PROBLEM: When I select File > Import and navigate to the folder the backup data file is stored in, the keychain backup files are greyed-out, and not selectable. Without being able to select the file at that stage in the task, I'm unable to proceed.

Given that, how do I proceed and accomplish my intended outcome: getting started with 1Password v7.7 and importing the data that I had from the old version of 1Password I was previously using?

1Password Version: From 3.8 to 7.7
Extension Version: Not Provided
OS Version: MacOS Mohave 10.14.6
Sync Type: Not Provided