This is the JSON for the structure used with the comment custom fragment

Comment_Test_Structure.json

{
	"availableLanguageIds": [
		"en_US"
	],
	"contentType": "journal",
	"dataDefinitionFields": [
		{
			"customProperties": {
				"labelAtStructureLevel": true,
				"confirmationErrorMessage": {
					"en_US": ""
				},
				"hideField": false,
				"dataType": "string",
				"tooltip": {
					"en_US": ""
				},
				"requireConfirmation": false,
				"displayStyle": "singleline",
				"visibilityExpression": "",
				"requiredErrorMessage": {
					"en_US": ""
				},
				"fieldNamespace": "",
				"objectFieldName": "",
				"options": {
				},
				"nativeField": false,
				"confirmationLabel": {
					"en_US": ""
				},
				"fieldReference": "Title",
				"placeholder": {
					"en_US": ""
				},
				"direction": [
					"vertical"
				]
			},
			"defaultValue": {
				"en_US": ""
			},
			"fieldType": "text",
			"indexType": "keyword",
			"indexable": true,
			"label": {
				"en_US": "Title"
			},
			"localizable": true,
			"name": "Text41538033",
			"nestedDataDefinitionFields": [
			],
			"readOnly": false,
			"repeatable": false,
			"required": false,
			"showLabel": true,
			"tip": {
				"en_US": ""
			}
		},
		{
			"customProperties": {
				"visibilityExpression": "",
				"requiredErrorMessage": {
					"en_US": ""
				},
				"fieldNamespace": "",
				"objectFieldName": "",
				"dataType": "string",
				"fieldReference": "Body"
			},
			"defaultValue": {
				"en_US": ""
			},
			"fieldType": "rich_text",
			"indexType": "text",
			"indexable": true,
			"label": {
				"en_US": "Body"
			},
			"localizable": true,
			"name": "RichText90858274",
			"nestedDataDefinitionFields": [
			],
			"readOnly": false,
			"repeatable": false,
			"required": false,
			"showLabel": true,
			"tip": {
				"en_US": ""
			}
		},
		{
			"customProperties": {
				"visibilityExpression": "",
				"requiredErrorMessage": {
					"en_US": ""
				},
				"fieldNamespace": "",
				"objectFieldName": "",
				"dataType": "image",
				"requiredDescription": true,
				"fieldReference": "bannerImage"
			},
			"defaultValue": {
				"en_US": {
				}
			},
			"fieldType": "image",
			"indexType": "text",
			"indexable": true,
			"label": {
				"en_US": "Banner Image"
			},
			"localizable": true,
			"name": "Image09486274",
			"nestedDataDefinitionFields": [
			],
			"readOnly": false,
			"repeatable": false,
			"required": false,
			"showLabel": true,
			"tip": {
				"en_US": ""
			}
		},
		{
			"customProperties": {
				"visibilityExpression": "",
				"requiredErrorMessage": {
					"en_US": ""
				},
				"fieldNamespace": "",
				"labelAtStructureLevel": true,
				"objectFieldName": "",
				"dataType": "boolean",
				"options": {
				},
				"fieldReference": "showComments",
				"showAsSwitcher": true
			},
			"defaultValue": {
				"en_US": [
					"false"
				]
			},
			"fieldType": "checkbox",
			"indexType": "keyword",
			"indexable": true,
			"label": {
				"en_US": "Show Comments"
			},
			"localizable": true,
			"name": "Checkbox59314661",
			"nestedDataDefinitionFields": [
			],
			"readOnly": false,
			"repeatable": false,
			"required": false,
			"showLabel": true,
			"tip": {
				"en_US": ""
			}
		}
	],
	"defaultDataLayout": {
		"dataLayoutFields": {
		},
		"dataLayoutPages": [
			{
				"dataLayoutRows": [
					{
						"dataLayoutColumns": [
							{
								"columnSize": 12,
								"fieldNames": [
									"Text41538033"
								]
							}
						]
					},
					{
						"dataLayoutColumns": [
							{
								"columnSize": 12,
								"fieldNames": [
									"RichText90858274"
								]
							}
						]
					},
					{
						"dataLayoutColumns": [
							{
								"columnSize": 12,
								"fieldNames": [
									"Image09486274"
								]
							}
						]
					},
					{
						"dataLayoutColumns": [
							{
								"columnSize": 12,
								"fieldNames": [
									"Checkbox59314661"
								]
							}
						]
					}
				],
				"description": {
					"en_US": ""
				},
				"title": {
					"en_US": ""
				}
			}
		],
		"dataRules": [
		],
		"description": {
		},
		"name": {
			"en_US": "Comment Test Structure"
		},
		"paginationMode": "single-page"
	},
	"defaultLanguageId": "en_US",
	"description": {
	},
	"name": {
		"en_US": "Comment Test Structure"
	},
	"storageType": "default"
}