You have to cut your template into components and replace class attribute with className.
var MyComponent = React.createClass({
  render: function() {
    return (
      <div className="my-class">
        Hello, world!
      </div>
    );
  }
});
ReactDOM.render(
  <MyComponent />,
  document.getElementById('content')
);
Take a look at official tutorial
But I strongly recommend you to read the documentation first and only then ask specific questions about what you did not understand.
solved Using react with a html template [closed]