If you have the pump characteristic curves from your pump supplier and already managed to plot the system resistance curve for the piping system you are designing then it is really very easy to finalize the selection of pump.
All you need to do is to find out the intersection points of the different pump head curves and the system curve. Each of the intersection points represents the working point of the pump.
For the above graph, which is showing the centrifugal pump curve and system curve, the working point is around 225 GPM discharge flow rate and 47 ft discharge pressure head.
You will get multiple intersection points (working point) at the intersections of multiple pump curves with your system curve.
Select the pump whose working point is closely matching your application requirements.