Beurer TENS EM29 help

November2

Have bought my father the Beurer Tens machine EM29 for his knee arthritis but instructions are not too helpful.  There are 4 programmes to choose from but it doesn't say which programme a beginner should start with or give any guidance with regards the intensity levels.  Does anyone have one of these machines and can help start us off with the correct programme and settings.

MovingForwards

https://www.beurer.com/web/gb/products/medical/electrostimulation/tens-ems/em-29-2-in-1.php

There's a video explaining.

With other tens machines I've used, I pick the setting which feels the most relaxing or beneficial, then start with lowest intensity working up until I start to feel relief.