Hi Martin,
On the Slider's on change event, you need to define handler passing value for the selected range where your slider is currenly.

In its action, you can assign value of 'Selected Value' to screen variable as below:

And regarding Max value and Min Value, you can create variables inside screen named as Maxvalue (default value 10) and MinValue (default value 1) as per your convenience, so you can directly use them inside your code.
Pass them as below:

This way you will be able to use SelectedRange, MinValue and MaxValue both inside your code.
Hope this helps, Thanks :)