The comments made on a post or page of a WordPress blog are stored in database and shown in a order with respect to their dates. By default, the comments are shown in an order such that the most recent comments are at the top.
If you want to change the order or want to show the older comments at top, then follow the below procedure.
Login to your WordPress dashboard. Go to
Setting >> Discussion.
Now select the “newer” / “older” comments at the top as shown in the picture.
Then save the changes and your comments will be shown according to the order you selected.