Scratch

I've got the first part of a graph-plotting project working but to make it useful for investigation, two sliders need to directly influence the values of two variables (F1 and F2). What happens at the moment is that the sliders show values as normal but don't influence the variables. They always start with F1=1 and F2=2. They then update their display as you'd expect when I run the program - but I don't know how to use the sliders at the outset to set the starting value of the variables.

Also - how do you specify the minimum/maximum range for sliders? (something like -100 to 100)

Once that's all solved, I have to find a way to scale the graph because output values are very small. I know I can multiply them by a fixed value (50) and that works OK - but I need the true result to be seen and obvious. Maybe I need to create an additional variable which divides the result by 50 and displays that?  Feels complicated and clumsy but I can't think of much else at the moment.