I didn't move after retirement, but I moved 30 times until I ended up where I am (and hopefully will stay here for the rest of my life). I hate moving!
By nature, and by habit, I am a shy introvert. But, being shy or an introvert is a luxury that I can't afford after a move, until establishing sufficient friendships in the new location.
So, after each move, I did all my chores, laundry, and grocery shopping during the week. Then I devoted 24 hours a day throughout the entire weekend to doing things that would allow me to be around potential friends with like interests. This is like pulling teeth for an introvert but you gotta do what you gotta do. There are a lot of good suggestions on this thread so think about them and think about which ones would most easily result in new friendships with compatible people. You can't make friends if you stay at home alone.
Oh, and one tip: No matter where you are moving, people will tell you that it's hard to make friends there, that the locals are very clannish and exclude outsiders, and so on. Or at least people told ME that. You should have heard what my Baton Rouge friends said about how clannish New Orleanians are!!
Not so. In my experience if you appreciate the new town and local culture and how things are done there, rather than trying to bring your old town with you, then people everywhere are reasonably receptive to newcomers. Of course some may not have room in their lives for another friend, but that's not their fault and you will be meeting lots of others as well.