well for the switch i would go to a eletrical supply house and pick one up there that its rated for your motor
as for the piping lay out you have suction line from the tank to the pump then the presure line out to the valve then outlet lines to the ram(they should be marked on the valve ) then a return line to the tank as for the postion of the valve lever i like my self to have the down stroke of the ram so you have to lift the valve handle up that way if you slip or fall on the handle the press will go up but thats my 2 cents and i would put quick disconects on the power lines so i could power other equitment in the future with the same pump