They make little clay/pottery things for that; but all you really need to do is lop off the very top, wrap the bulb(s) in foil (I would sprinkle some olive oil on) and roast. Here’s a link:
http://www.thekitchn.com/how-to-roast-garlic-in-the-oven-cooking-lessons-from-the-kitchn-5341
The resulting paste is wonderful on buttered Italian bread.
-JT
Yes, that’s the easiest way to roast garlic - plus it fills the home with that wonderful smell. And the garlic becomes as sweet as candy.
Was out last night and had it. Long time ago mom had one of those clay things but for some reason didn’t work very well. I’ll try the foil thing. Thanks. Janey