Google Slides are your thing, but you need some place to start?  At SlidesMania, all templates are FREE and give you beautiful pre-made presentations you can edit to your liking.  Did I mention it's FREE?  Just be aware that there are ads- scroll down and look for the "Open in Google Slides" button to open the template.  Preview what it looks like and click the blue "Use Template" button in the top right corner.

Not only does Canva make your graphic designs come to life, but it also has pre-made presentations that you can edit to your liking!  Everything in Canva is editable!  You can search for a specific topic to see if they have a pre-made presentation OR search for a style of presentation you like and fill it with your own curriculum content.