Hi,
I've attached a sample oml with a working example of the split screen pattern.
Keep in mind that you can only actually see the split screen in a tablet. In mobile, as it says in the documentation, it will adapt to the phone layout by showing only one panel at each time.
I'm using Outsystems 11 and therefore I'm using Outsystems UI instead of Silk UI, but it's pretty much the same.
Hope this helps. Let me know if you have any questions.
Best regards,
André