That looks like Object Styles. You can select them and delete them directly in the panel, but you'd be far wiser to examine what they are set to do and use them.
Styles are the way you maintain consistency across your document and allow you to make a change in one place (the style definition) that will ripple through the entire documetn and change everything to which that style is applied.
I sense you are inexperienced, and this may be a more complex job than you are ready to tackle. Some training might be a good thing. Sandee Cohen's Visual QuickStart Guide to InDesing is an excellent beginners book, and you won't find better video training than Lynda.com.