What kind of speakers and sound equipment would I need for an outdoors party?

My friend and I are throwing a party in the summer. It is going to be outdoors with fairy lights, food and drinks. And music.

I know nothing about music technology – what do I need just to play CDs through several big speakers, and it needs to be loud!

How to connect and hire (only needed for a day) as well please.
Very confused!

You can google it. Good luck!