My example patch here also shows some ways to cycle through videos/pictures: https://troikatronix.com/add-ons/random-media-random-duration/

Here's another option, switching between 2 sources at 1hz.

I have to recommend my tutorial on creating a video step sequencer.
It teaches you about routing, video mixing and much more. It's an intermediate tutorial but is sure to teach you some core patching fundamentals.

welcome to the izzy community and the endless world of isadora media server!

This would be the most easiest solution, if you need to go back and forth.

If you just need to go from one movie to another, you can use the scenes and jump between them by hitting space:

But in general I can really recommend the tutorials. Izzy is powerfull and when the basics are understood, has a steep learning curve. But it can be a bit irritating at the beginning, as it works different to most other media tools, and it always offers many different ways to similar goals. It always depends on the details of what you want to achieve.

That's why I'd like to give an advise for asking a question in the forum; Always be as specific as possible in what you like to achieve. The more, the better someone here can give you advise.

Have fun