Validation Email with Checkbox

I need to click on the text "I accept the conditions of use and privacy policy", automatically check the checkbox, like this:

<label>
    <input type="checkbox" name="LOPD" id="LOPD">I accept <a href="http://www.google.es/aviso-legal/" target="blank">conditions of use</a> and <a href="http://www.google.es/politica-de-privacidad/" target="blank">privacy policy</a>
</label>

A greater, that the message div with the label "validation", in case it is not marked, appears below with the style sheets as it appears in the email field.

Any suggestions?

I have a example, in which the message comes out next to the checkbox because it is not done in another way

https://jsfiddle.net/mf0sk13e/18/