Good evening, my name is ***** ***** I will do my best to assist you.
My apologies that no one replied to you sooner. If you dont have imovie on your mac, then we will either need to purchase Imovie, or we will need to use an alternate software.
You can get the ilife suite, which includes imovie here.. http://amzn.to/1VUrOB8
Or, you can try a software such as iskysofts slideshow maker.. https://www.iskysoft.com/slideshow-maker-mac.html
there both about the same price, and they both do very similar things. But the ilife suite also comes with idvd, garage band ( to edit music files ) and iweb ( to easily make websites if you wanted )
All in all, the ilife suite is probably a better deal, and has more bundled and useful software with it.
With imovie, its very easy to make the slideshow. This page, has a beginning to end tutorial that will teach you how to make a movie. If you follow along this page , by the end of it you will have created your movie, added the pictures, added the music, and picked out different themes, and transition effects ( the effects you see when it changes from picture to picture )
If you have any further questions, let me know!
I strive to provide great service, and greatly appreciate a rating of excellent ( 5 stars ) selected and submitted below this answer or at the top right of the screen. I always answer follow up questions.
Senior Technician and Network Switching Systems Operator / Maintainer.