Select Element in DOM with Xpath expression or bt class name

Hi

I want to select different themes such as Gray Theme, Navy Theme etc.

I tried below scenario:-
"scenarios": [
{

"label": "accord blue",
"url": "",
"delay": 3000,
"selectorExpansion": true,

"clickselector":['button.btn.btn-primary'],

"postInteractionWait": 200,

"misMatchThreshold": 5,
"onBeforeScript": "onBefore.js",
"onReadyScript": "onReady.js"
}

]

I can see that it just load the page with the URL and take screenshot. It does not click on the button. Does it support Xpath expressions such as:-
//button[@onclick='themeClickSkyBlue()']?
Do you have any recommendation to work on this.