Custom CSS class

Hello,

I want to change the word “Tempo” (h3) inside of the “mec-single-event-time” class to something else. By inspecting the element I get this:

<div class="mec-single-event-time">
	<i class="mec-sl-clock " style=""></i>
	<h3 class="mec-time">Tempo</h3>
	<i class="mec-time-comment"></i>
	<dl>
		<dd><abbr class="mec-events-abbr">09:00 - 10:30</abbr></dd>
	</dl>
</div>

How could I do it? I am not a developer, so please provide details.

Thanks,