To activate old Prezi Classic player:
First, enable Flash Player in your browser.
To see animation, click switch back to go back to the old viewer.
For example you can test and see flash animation in Prezi here: https://prezi.com/bqkhzk7em-qa/in-front-of-a-choice
New link on address bar should be like this: https://prezi.com/bqkhzk7em-qa/in-front-of-a-choice/?webgl=0
Before purchasing an animated Prezi template you can test for free and make a copy from this Prezi:
After clicking a link (https://prezi.com/bqkhzk7em-qa/in-front-of-a-choice/), make a copy of a Prezi (by pressing the button “Save a copy”).
To see Prezi classic templates, at your Prezi account switch back to Prezi Classic view. Then you will see all Prezis that are made with previous version (known as classic)
Same way you can edit and change all other animated templates (technology animated for example):