Lee Markum has an after-action report:
In late 2019, a project that had been in progress for well over a year finally came to a conclusion. I had collaborated with a number of people to migrate a stand alone SQL Server 2008 and two stand alone SQL Server 2008 R2 instances. Each stand alone SQL Server was migrated to a three node Availability Group. Here are a few things learned along the way.
Click through for some good advice.