Proportional Flow Control Valve with Controller

Hi, many thanks for shaing feedback. Based on your reply, I have remodelled my circuit set-up with an N-Channel Mosfet (unsure if this is the right choice). I believe resistors would have to be added in and I am unsure on the rigth way to determine the value of these resistors. Would appreciate if you could have a look at my diagram and provide feedback if I am on the rigth track: