How can I eneable 2 Functions at Once?

Hey there hope you can help me. I want to Change the Color of my Iphone and if the Screen is turned on at once. I get a Function for both of it and toggle it in the Material with scalar Parameters. But how can I eneable both at the same time if I set them in a row in the construction scipt I only can enebale the last function.

The text is a bit hard to make out, but what I think is happening here is that your second function (Color) is clobbering the MaterialInstance that you created and saved in the OnOff function. You should only need to create the MaterialInstance once. Since you save it to a variable, you can then access that later.
In the Color function, try removing the “Create Dynamic Material Instance” and the following “Set Variable” nodes (in both places). You should end up with a simpler function that simply sets the Scalar parameters on the MaterialInstance that you already have.