When making a modification to your website, a good practice is to create a duplicate module at the bottom of the page. That way, if you mess something up, you still have an original.
Create a duplicate module at the bottom of the page to play around and see how it will look rather than editing the current module. To do this, click on the pencil icon to open the module for editing. Highlight all the text and press CTRL+C (copy). Open the new module and press CTRL+V (paste). Make your edits to the new one. When you have the new one looking how you want, go ahead and delete the old one.