As the people bring their children to Jesus they sit them on the ground “round about” him. They are in a rough circular pattern around him. In this size population there would naturally be several children, so there was not a single ring, but a massed ring of children around the Savior.
As he begins, he requests the multitude that they kneel. We do not know if there was a culturally known pattern of kneeling out of reverence, but since we do know that being overcome by the spirit could cause one to fall to the earth (as did the entire congregation after Benjamin’s discourse, Mosiah 4:1) it is probable that the kneeling informed this particular audience that they were about to engage in a particularly spiritual occasion.