Hello, I wanna know how can I change value of constant in Simluink from GUI and how can i show the result of scope in simulink form GUI when change value of constant?

in this picture, i have a constant (references speed ) and subsystem (it has BLDC motor produce with PLECS) and scope (shows result of speed ). i don't know how can i change value of constant and show result that with scope from GUI.

Thank you so much