to call a function from script, you can use the "call method action" you can also use invoke method, to use logic like you asked, you can use a public bool and when you're in the function set it to true, in playmaker you can test the bool by dragging the script into your fsm, when the bool is true fire an event.
in the second problem drag the script in and select the "get" option, get the float you want to multiply and then multiply it using the float multiply action.