Checkbox/Multiple Checkbox/Radio

Checkbox

{
    "on" : "On Text",
    "off" : "Off Text",
    "checked" : true
}

In Voyager a Checkbox is converted into a toggle switch, and as you can see above the on key will contain the value when the toggle switch is on, and the off will contain the value that is set when the switch is off. If checked is set to true the checkbox will be toggle on; otherwise by default it will be off.

Multiple Checkbox

{
    "checked" : true,
    "options": {
        "checkbox1": "Checkbox 1 Text",
        "checkbox2": "Checkbox 2 Text"
    }
}

You can create as many checkboxes as you want.

Radio Button

{
    "default" : "radio1",
    "options" : {
        "radio1": "Radio Button 1 Text",
        "radio2": "Radio Button 2 Text"
    }
}

The Radio button is exactly the same as the dropdown. You can specify a default if one has not been set and in the options object you will specify the value of the option on the left and the text to be displayed on the right.